soundwire: slave: add first_interrupt_done status

Some Slaves report incorrect information in their interrupt status
registers after a master/bus reset, track the initial interrupt
handling so that quirks can be introduced to filter out incorrect
information while keeping interrupts enabled in steady state.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Link: https://lore.kernel.org/r/20200908134521.6781-4-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/bus.c

@@ -1472,6 +1472,9 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 			goto io_err;
 		}
 
+		/* at this point all initial interrupt sources were handled */
+		slave->first_interrupt_done = true;
+
 		/*
 		 * Read status again to ensure no new interrupts arrived
 		 * while servicing interrupts.
@@ -1674,8 +1677,10 @@ void sdw_clear_slave_status(struct sdw_bus *bus, u32 request)
 		if (!slave)
 			continue;
 
-		if (slave->status != SDW_SLAVE_UNATTACHED)
+		if (slave->status != SDW_SLAVE_UNATTACHED) {
 			sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
+			slave->first_interrupt_done = false;
+		}
 
 		/* keep track of request, used in pm_runtime resume */
 		slave->unattach_request = request;

drivers/soundwire/slave.c

@@ -58,6 +58,7 @@ static int sdw_slave_add(struct sdw_bus *bus,
 	slave->dev_num = 0;
 	init_completion(&slave->probe_complete);
 	slave->probed = false;
+	slave->first_interrupt_done = false;
 
 	for (i = 0; i < SDW_MAX_PORTS; i++)
 		init_completion(&slave->port_ready[i]);

include/linux/soundwire/sdw.h

@@ -616,6 +616,8 @@ struct sdw_slave_ops {
  * between the Master suspending and the codec resuming, and make sure that
  * when the Master triggered a reset the Slave is properly enumerated and
  * initialized
+ * @first_interrupt_done: status flag tracking if the interrupt handling
+ * for a Slave happens for the first time after enumeration
  */
 struct sdw_slave {
 	struct sdw_slave_id id;
@@ -637,6 +639,7 @@ struct sdw_slave {
 	struct completion enumeration_complete;
 	struct completion initialization_complete;
 	u32 unattach_request;
+	bool first_interrupt_done;
 };
 
 #define dev_to_sdw_dev(_dev) container_of(_dev, struct sdw_slave, dev)