drm/etnaviv: don't move linear memory window on 3D cores without MC2.0

On cores with MC1.0 the memory window offset is not properly respected
by all engines in the core, leading to different views of the memory
if the offset in non-zero. This causes relocs for those engines to be
wrong and might lead to other subtile problems.

Rather than trying to work around this, just disable the linear memory
window offset for those cores.
Suggested-by: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -572,6 +572,24 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
 		goto fail;
 	}
 
+	/*
+	 * Set the GPU linear window to be at the end of the DMA window, where
+	 * the CMA area is likely to reside. This ensures that we are able to
+	 * map the command buffers while having the linear window overlap as
+	 * much RAM as possible, so we can optimize mappings for other buffers.
+	 *
+	 * For 3D cores only do this if MC2.0 is present, as with MC1.0 it leads
+	 * to different views of the memory on the individual engines.
+	 */
+	if (!(gpu->identity.features & chipFeatures_PIPE_3D) ||
+	    (gpu->identity.minor_features0 & chipMinorFeatures0_MC20)) {
+		u32 dma_mask = (u32)dma_get_required_mask(gpu->dev);
+		if (dma_mask < PHYS_OFFSET + SZ_2G)
+			gpu->memory_base = PHYS_OFFSET;
+		else
+			gpu->memory_base = dma_mask - SZ_2G + 1;
+	}
+
 	ret = etnaviv_hw_reset(gpu);
 	if (ret)
 		goto fail;
@@ -1566,7 +1584,6 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct etnaviv_gpu *gpu;
-	u32 dma_mask;
 	int err = 0;
 
 	gpu = devm_kzalloc(dev, sizeof(*gpu), GFP_KERNEL);
@@ -1576,18 +1593,6 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 	gpu->dev = &pdev->dev;
 	mutex_init(&gpu->lock);
 
-	/*
-	 * Set the GPU linear window to be at the end of the DMA window, where
-	 * the CMA area is likely to reside. This ensures that we are able to
-	 * map the command buffers while having the linear window overlap as
-	 * much RAM as possible, so we can optimize mappings for other buffers.
-	 */
-	dma_mask = (u32)dma_get_required_mask(dev);
-	if (dma_mask < PHYS_OFFSET + SZ_2G)
-		gpu->memory_base = PHYS_OFFSET;
-	else
-		gpu->memory_base = dma_mask - SZ_2G + 1;
-
 	/* Map registers: */
 	gpu->mmio = etnaviv_ioremap(pdev, NULL, dev_name(gpu->dev));
 	if (IS_ERR(gpu->mmio))