+ /* NULL rx means write-only transfer and no map needed
+ * since rx DMA will not be used */
+ if (drv_data->rx) {
+ buf = drv_data->rx;
+ drv_data->rx_dma = dma_map_single(dev,
+ buf,
+ drv_data->len,
+ DMA_FROM_DEVICE);
+ if (dma_mapping_error(dev, drv_data->rx_dma)) {
+ if (drv_data->tx_dma) {
+ dma_unmap_single(dev,
+ drv_data->tx_dma,
+ drv_data->tx_map_len,
+ DMA_TO_DEVICE);
+ drv_data->tx_dma_needs_unmap = 0;
+ }
+ return -1;
+ }
+ drv_data->rx_dma_needs_unmap = 1;
+ }
+