iommu/dart: Allow locked DARTs to probe

Instead of bailing from reset() if the DART is locked, simply skip the
reset for locked DARTs.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>

Author: alyssarosenzweig

drivers/iommu/apple-dart.c

@@ -451,17 +451,9 @@ apple_dart_t8110_hw_invalidate_tlb(struct apple_dart_stream_map *stream_map)
 
 static int apple_dart_hw_reset(struct apple_dart *dart)
 {
-	u32 config;
 	struct apple_dart_stream_map stream_map;
 	int i;
 
-	config = readl(dart->regs + dart->hw->lock);
-	if (config & dart->hw->lock_bit) {
-		dev_err(dart->dev, "DART is locked down until reboot: %08x\n",
-			config);
-		return -EINVAL;
-	}
-
 	stream_map.dart = dart;
 	bitmap_zero(stream_map.sidmap, DART_MAX_STREAMS);
 	bitmap_set(stream_map.sidmap, 0, dart->num_streams);
@@ -1122,9 +1114,11 @@ static int apple_dart_probe(struct platform_device *pdev)
 	dart->force_bypass = dart->pgsize > PAGE_SIZE;
 
 	dart->locked = apple_dart_is_locked(dart);
-	ret = apple_dart_hw_reset(dart);
-	if (ret)
-		goto err_clk_disable;
+	if (!dart->locked) {
+		ret = apple_dart_hw_reset(dart);
+		if (ret)
+			goto err_clk_disable;
+	}
 
 	ret = request_irq(dart->irq, dart->hw->irq_handler, IRQF_SHARED,
 			  "apple-dart fault handler", dart);