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

[karo-tx-linux.git] / drivers / of / device.c

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 28e7438884029e1f1bf56b6f09632cf1479584f5..20c1332a00182cb43bb707e2a7468dce73cdf991 100644 (file)
--- a/drivers/of/device.c
+++ b/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 ");