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-rw-r--r--drivers/of/device.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 28e74388..20c1332 100644
--- 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 ");
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