fixup! soundwire: cadence: re-check Peripheral status with delayed_work

Add mutual exclusion so that the interrupt and delayed work cannot
update the status concurrently.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>

drivers/soundwire/cadence_master.c

@@ -891,8 +891,14 @@ static int cdns_update_slave_status(struct sdw_cdns *cdns,
 		}
 	}
 
-	if (is_slave)
-		return sdw_handle_slave_status(&cdns->bus, status);
+	if (is_slave) {
+		int ret;
+
+		mutex_lock(&cdns->status_update_lock);
+		ret = sdw_handle_slave_status(&cdns->bus, status);
+		mutex_unlock(&cdns->status_update_lock);
+		return ret;
+	}
 
 	return 0;
 }
@@ -998,14 +1004,6 @@ static void cdns_check_attached_status_dwork(struct work_struct *work)
 	int ret;
 	int i;
 
-	/*
-	 * Mask the Slave interrupt while we try to update the status.
-	 * This will prevent concurrent execution of this delayed_work
-	 * and the regular update_status_work as a result of programming
-	 * the device number to a non-zero value.
-	 */
-	cdns_updatel(cdns, CDNS_MCP_INTMASK, CDNS_MCP_INT_SLAVE_MASK, 0);
-
 	val = cdns_readl(cdns, CDNS_MCP_SLAVE_STAT);
 
 	for (i = 0; i <= SDW_MAX_DEVICES; i++) {
@@ -1015,13 +1013,13 @@ static void cdns_check_attached_status_dwork(struct work_struct *work)
 		val >>= 2;
 	}
 
+	mutex_lock(&cdns->status_update_lock);
 	ret = sdw_handle_slave_status(&cdns->bus, status);
+	mutex_unlock(&cdns->status_update_lock);
 	if (ret < 0)
 		dev_err(cdns->dev, "%s: sdw_handle_slave_status failed: %d\n", __func__, ret);
-
-	/* unmask Slave interrupt now */
-	cdns_updatel(cdns, CDNS_MCP_INTMASK, CDNS_MCP_INT_SLAVE_MASK, CDNS_MCP_INT_SLAVE_MASK);
 }
+
 /**
  * cdns_update_slave_status_work - update slave status in a work since we will need to handle
  * other interrupts eg. CDNS_MCP_INT_RX_WL during the update slave
@@ -1774,6 +1772,8 @@ int sdw_cdns_probe(struct sdw_cdns *cdns)
 	init_completion(&cdns->tx_complete);
 	cdns->bus.port_ops = &cdns_port_ops;
 
+	mutex_init(&cdns->status_update_lock);
+
 	INIT_WORK(&cdns->work, cdns_update_slave_status_work);
 	INIT_DELAYED_WORK(&cdns->attach_dwork, cdns_check_attached_status_dwork);
 

drivers/soundwire/cadence_master.h

@@ -117,6 +117,8 @@ struct sdw_cdns_dai_runtime {
  * @link_up: Link status
  * @msg_count: Messages sent on bus
  * @dai_runtime_array: runtime context for each allocated DAI.
+ * @status_update_lock: protect concurrency between interrupt-based and delayed work
+ * status update
  */
 struct sdw_cdns {
 	struct device *dev;
@@ -153,6 +155,8 @@ struct sdw_cdns {
 	struct list_head list;
 
 	struct sdw_cdns_dai_runtime **dai_runtime_array;
+
+	struct mutex status_update_lock; /* add mutual exclusion to sdw_handle_slave_status() */
 };
 
 #define bus_to_cdns(_bus) container_of(_bus, struct sdw_cdns, bus)