drivers/spi/spi-bcm2835.c

153  * @clear_rx_desc: preallocated RX DMA descriptor used for TX-only transfers
161 	struct dma_async_tx_descriptor *clear_rx_desc;
818 		cookie = dmaengine_submit(target->clear_rx_desc);
1156 	if (target->clear_rx_desc)
1157 		dmaengine_desc_free(target->clear_rx_desc);
1191 	target->clear_rx_desc = dmaengine_prep_dma_cyclic(ctlr->dma_rx,
1195 	if (!target->clear_rx_desc) {
1196 		dev_err(&spi->dev, "cannot prepare clear_rx_desc\n");
1200 	ret = dmaengine_desc_set_reuse(target->clear_rx_desc);
1202 		dev_err(&spi->dev, "cannot reuse clear_rx_desc\n");