media: ddbridge: improve separated MSI IRQ handling

Improve IRQ handling in the separated MSG/I2C and IO/TSDATA handlers by
applying a mask for recognized bits immediately upon reading the IRQ mask
from the hardware, so only the bits/IRQs that actually were set will be
acked.

Picked up from the upstream dddvb-0.9.33 release.
Signed-off-by: Daniel Scheller <d.scheller@gmx.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/pci/ddbridge/ddbridge-core.c

@@ -2428,16 +2428,17 @@ static void irq_handle_io(struct ddb *dev, u32 s)
 irqreturn_t ddb_irq_handler0(int irq, void *dev_id)
 {
 	struct ddb *dev = (struct ddb *)dev_id;
-	u32 s = ddbreadl(dev, INTERRUPT_STATUS);
+	u32 mask = 0x8fffff00;
+	u32 s = mask & ddbreadl(dev, INTERRUPT_STATUS);
 
+	if (!s)
+		return IRQ_NONE;
 	do {
 		if (s & 0x80000000)
 			return IRQ_NONE;
-		if (!(s & 0xfffff00))
-			return IRQ_NONE;
-		ddbwritel(dev, s & 0xfffff00, INTERRUPT_ACK);
+		ddbwritel(dev, s, INTERRUPT_ACK);
 		irq_handle_io(dev, s);
-	} while ((s = ddbreadl(dev, INTERRUPT_STATUS)));
+	} while ((s = mask & ddbreadl(dev, INTERRUPT_STATUS)));
 
 	return IRQ_HANDLED;
 }
@@ -2445,16 +2446,17 @@ irqreturn_t ddb_irq_handler0(int irq, void *dev_id)
 irqreturn_t ddb_irq_handler1(int irq, void *dev_id)
 {
 	struct ddb *dev = (struct ddb *)dev_id;
-	u32 s = ddbreadl(dev, INTERRUPT_STATUS);
+	u32 mask = 0x8000000f;
+	u32 s = mask & ddbreadl(dev, INTERRUPT_STATUS);
 
+	if (!s)
+		return IRQ_NONE;
 	do {
 		if (s & 0x80000000)
 			return IRQ_NONE;
-		if (!(s & 0x0000f))
-			return IRQ_NONE;
-		ddbwritel(dev, s & 0x0000f, INTERRUPT_ACK);
+		ddbwritel(dev, s, INTERRUPT_ACK);
 		irq_handle_msg(dev, s);
-	} while ((s = ddbreadl(dev, INTERRUPT_STATUS)));
+	} while ((s = mask & ddbreadl(dev, INTERRUPT_STATUS)));
 
 	return IRQ_HANDLED;
 }