[PATCH] of/platform: Initialise AMBA default DMA masks

[Christoph Hellwig]

>  	/* setup generic device info */
> +	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> +	if (!dev->dev.dma_mask)
> +		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;

We should never set dma_mask to point to the coherent_dma_mask,
as that will cause problems with devices that have different
mask for the two.

How about something like this?

---
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 7ba90c290a42..c04ed124305c 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -242,6 +242,9 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
 		goto err_clear_flag;
 
 	/* setup generic device info */
+	dev->dma_mask = DMA_BIT_MASK(32);
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	dev->dev.dma_mask = &dev->dma_mask;
 	dev->dev.of_node = of_node_get(node);
 	dev->dev.fwnode = &node->fwnode;
 	dev->dev.parent = parent ? : &platform_bus;
diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
index d143c13bed26..fbc7adf3ca54 100644
--- a/include/linux/amba/bus.h
+++ b/include/linux/amba/bus.h
@@ -34,6 +34,7 @@ struct amba_device {
 	unsigned int		periphid;
 	unsigned int		irq[AMBA_NR_IRQS];
 	char			*driver_override;
+	u64			dma_mask;
 };
 
 struct amba_driver {