65 lines
1.8 KiB
C
65 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_DMA_MAPPING_H
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#define _LINUX_DMA_MAPPING_H
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#include <asm/cache.h>
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#include <linux/dma-direction.h>
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#include <linux/types.h>
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#include <asm/dma-mapping.h>
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#include <cpu_func.h>
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#define dma_mapping_error(x, y) 0
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/**
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* Map a buffer to make it available to the DMA device
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*
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* Linux-like DMA API that is intended to be used from drivers. This hides the
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* underlying cache operation from drivers. Call this before starting the DMA
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* transfer. In most of architectures in U-Boot, the virtual address matches to
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* the physical address (but we have exceptions like sandbox). U-Boot does not
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* support iommu at the driver level, so it also matches to the DMA address.
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* Hence, this helper currently just performs the cache operation, then returns
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* straight-mapped dma_address, which is intended to be set to the register of
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* the DMA device.
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*
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* @vaddr: address of the buffer
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* @len: length of the buffer
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* @dir: the direction of DMA
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*/
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static inline dma_addr_t dma_map_single(void *vaddr, size_t len,
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enum dma_data_direction dir)
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{
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unsigned long addr = (unsigned long)vaddr;
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len = ALIGN(len, ARCH_DMA_MINALIGN);
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if (dir == DMA_FROM_DEVICE)
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invalidate_dcache_range(addr, addr + len);
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else
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flush_dcache_range(addr, addr + len);
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return addr;
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}
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/**
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* Unmap a buffer to make it available to CPU
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*
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* Linux-like DMA API that is intended to be used from drivers. This hides the
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* underlying cache operation from drivers. Call this after finishin the DMA
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* transfer.
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*
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* @addr: DMA address
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* @len: length of the buffer
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* @dir: the direction of DMA
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*/
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static inline void dma_unmap_single(dma_addr_t addr, size_t len,
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enum dma_data_direction dir)
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{
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len = ALIGN(len, ARCH_DMA_MINALIGN);
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if (dir != DMA_TO_DEVICE)
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invalidate_dcache_range(addr, addr + len);
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}
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#endif
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