On Tuesday 05 May 2015 10:12:06 Suravee Suthikulpanit wrote:

+struct dma_map_ops dummy_dma_ops = {
+       .alloc                  = __dummy_alloc,
+       .free                   = __dummy_free,
+       .mmap                   = __dummy_mmap,
+       .map_page               = __dummy_map_page,
+       .unmap_page             = __dummy_unmap_page,
+       .map_sg                 = __dummy_map_sg,
+       .unmap_sg               = __dummy_unmap_sg,
+       .sync_single_for_cpu    = __dummy_sync_single_for_cpu,
+       .sync_single_for_device = __dummy_sync_single_for_device,
+       .sync_sg_for_cpu        = __dummy_sync_sg_for_cpu,
+       .sync_sg_for_device     = __dummy_sync_sg_for_device,
+       .mapping_error          = __dummy_mapping_error,
+       .dma_supported          = __dummy_dma_supported,
+};
+EXPORT_SYMBOL(dummy_dma_ops);
+

This will clearly work, but I think it's easier to just leave
the dma_mask pointer as NULL when creating the platform device,
which should let the normal dma ops fail all the callbacks.

	Arnd