arm/mm/dma-mapping-nommu.c

1 // SPDX-License-Identifier: GPL-2.0-only
3  *  Based on linux/arch/arm/mm/dma-mapping.c
5  *  Copyright (C) 2000-2004 Russell King
10 #include <linux/dma-direct.h>
11 #include <linux/dma-map-ops.h>
19 #include "dma.h"
23  *   - MMU/MPU is off
24  *   - cpu is v7m w/o cache support
25  *   - device is coherent
28  *  arm_nommu_dma_ops rely on consistent DMA memory (please, refer to
31  *  [1] Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
44 	 * - no consistent DMA region has been defined, so we can't  in arm_nommu_dma_alloc()
46 	 * - there is no space left in consistent DMA region, so we  in arm_nommu_dma_alloc()
74 	return -ENXIO;  in arm_nommu_dma_mmap()
127 		sg_dma_len(sg) = sg->length;  in arm_nommu_dma_map_sg()
195 			const struct iommu_ops *iommu, bool coherent)  in arch_setup_dma_ops()  argument
200 		 * coherent if no cache has been detected. Note that it is not  in arch_setup_dma_ops()
204 		dev->archdata.dma_coherent = (cacheid) ? coherent : true;  in arch_setup_dma_ops()
207 		 * Assume coherent DMA in case MMU/MPU has not been set up.  in arch_setup_dma_ops()
209 		dev->archdata.dma_coherent = (get_cr() & CR_M) ? coherent : true;  in arch_setup_dma_ops()
212 	if (!dev->archdata.dma_coherent)  in arch_setup_dma_ops()