* Assume that they will -- if they turn out not to be, then we can
* take them out of the 1:1 domain later.
*/
- if (!startup)
- return pdev->dma_mask > DMA_BIT_MASK(32);
+ if (!startup) {
+ /*
+ * If the device's dma_mask is less than the system's memory
+ * size then this is not a candidate for identity mapping.
+ */
+ u64 dma_mask = pdev->dma_mask;
+
+ if (pdev->dev.coherent_dma_mask &&
+ pdev->dev.coherent_dma_mask < dma_mask)
+ dma_mask = pdev->dev.coherent_dma_mask;
+
+ return dma_mask >= dma_get_required_mask(&pdev->dev);
+ }
return 1;
}