iommu: apple-dart: Power on device when handling IRQs

It's possible for an IRQ to fire and the device to be RPM suspended
before we can handle it, which then causes device register accesses to
fail in the IRQ handler.

Since RPM is IRQ-safe for this device, just make sure we power on the
DART in the IRQ handler too.

Signed-off-by: Asahi Lina <lina@asahilina.net>

Author: hoshinolina

drivers/iommu/apple-dart.c

@@ -1228,6 +1228,17 @@ static irqreturn_t apple_dart_t8110_irq(int irq, void *dev)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t apple_dart_irq(int irq, void *dev)
+{
+	irqreturn_t ret;
+	struct apple_dart *dart = dev;
+
+	WARN_ON(pm_runtime_get_sync(dart->dev) < 0);
+	ret = dart->hw->irq_handler(irq, dev);
+	pm_runtime_put(dart->dev);
+	return ret;
+}
+
 static bool apple_dart_is_locked(struct apple_dart *dart)
 {
 	return !!(readl(dart->regs + dart->hw->lock) & dart->hw->lock_bit);
@@ -1307,7 +1318,7 @@ static int apple_dart_probe(struct platform_device *pdev)
 			goto err_clk_disable;
 	}
 
-	ret = request_irq(dart->irq, dart->hw->irq_handler, IRQF_SHARED,
+	ret = request_irq(dart->irq, apple_dart_irq, IRQF_SHARED,
 			  "apple-dart fault handler", dart);
 	if (ret)
 		goto err_clk_disable;