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-rw-r--r--include/linux/dma-mapping.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 8d13e28a8e07..e11b115dd0e4 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -679,6 +679,20 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
return dma_set_mask_and_coherent(dev, mask);
}
+/**
+ * dma_addressing_limited - return if the device is addressing limited
+ * @dev: device to check
+ *
+ * Return %true if the devices DMA mask is too small to address all memory in
+ * the system, else %false. Lack of addressing bits is the prime reason for
+ * bounce buffering, but might not be the only one.
+ */
+static inline bool dma_addressing_limited(struct device *dev)
+{
+ return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) <
+ dma_get_required_mask(dev);
+}
+
#ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent);
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