of: Calculate device DMA masks based on DT dma-range size

Calculate the dma_mask and coherent_dma_mask based on the dma-range values
set in DT for the device.

Limit the mask to lower of the default mask and mask calculated.

Signed-off-by: Murali Karicheri <[email protected]>
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Catalin Marinas <[email protected]>
CC: Joerg Roedel <[email protected]>
CC: Grant Likely <[email protected]>
CC: Rob Herring <[email protected]>
CC: Will Deacon <[email protected]>
CC: Russell King <[email protected]>
CC: Arnd Bergmann <[email protected]>
CC: Suravee Suthikulpanit <[email protected]>

drivers/of/device.c

@@ -90,10 +90,11 @@ void of_dma_configure(struct device *dev, struct device_node *np)
 	struct iommu_ops *iommu;
 
 	/*
-	 * Set default dma-mask to 32 bit.  Drivers are expected to setup
-	 * the correct supported dma_mask.
+	 * Set default coherent_dma_mask to 32 bit.  Drivers are expected to
+	 * setup the correct supported mask.
 	 */
-	dev->coherent_dma_mask = DMA_BIT_MASK(32);
+	if (!dev->coherent_dma_mask)
+		dev->coherent_dma_mask = DMA_BIT_MASK(32);
 
 	/*
 	 * Set it to coherent_dma_mask by default if the architecture
@@ -128,6 +129,15 @@ void of_dma_configure(struct device *dev, struct device_node *np)
 
 	dev->dma_pfn_offset = offset;
 
+	/*
+	 * Limit coherent and dma mask based on size and default mask
+	 * set by the driver.
+	 */
+	dev->coherent_dma_mask = min(dev->coherent_dma_mask,
+				     DMA_BIT_MASK(ilog2(dma_addr + size)));
+	*dev->dma_mask = min((*dev->dma_mask),
+			     DMA_BIT_MASK(ilog2(dma_addr + size)));
+
 	coherent = of_dma_is_coherent(np);
 	dev_dbg(dev, "device is%sdma coherent\n",
 		coherent ? " " : " not ");