soundwire: cadence: Clear interrupts before handling them

Clear interrupts before handling them in sdw_cdns_irq() to prevent
loasing events that re-triggered before they can be handled.

Clearing interrupts at the end of sdw_cdns_irq() is a potential race.
If the event re-triggered while sdw_cdns_irq() is still running it
would be cleared when sdw_cdns_irq() ends, so the irq handler would
not be re-triggered to handle it.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 2f52a51 ("soundwire: cdns: Add cadence library")

Author: rfvirgil

drivers/soundwire/cadence_master.c

@@ -950,6 +950,12 @@ irqreturn_t sdw_cdns_irq(int irq, void *dev_id)
 		}
 	}
 
+	/*
+	 * Clear interrupts before handling them so we don't lose
+	 * events that re-trigger while this code is running.
+	 */
+	cdns_writel(cdns, CDNS_MCP_INTSTAT, int_status);
+
 	if (int_status & CDNS_MCP_INT_PARITY) {
 		/* Parity error detected by Master */
 		dev_err_ratelimited(cdns->dev, "Parity error\n");
@@ -993,7 +999,6 @@ irqreturn_t sdw_cdns_irq(int irq, void *dev_id)
 			schedule_work(&cdns->work);
 	}
 
-	cdns_writel(cdns, CDNS_MCP_INTSTAT, int_status);
 	return IRQ_HANDLED;
 }
 EXPORT_SYMBOL(sdw_cdns_irq);