mirror of
https://github.com/smaeul/u-boot.git
synced 2025-11-04 14:00:19 +00:00
9d86b89c59
The implementation of dma_map_single() and dma_unmap_single() is exactly the same for all the architectures that support them. Factor them out to <linux/dma-mapping.h>, and make all drivers to include <linux/dma-mapping.h> instead of <asm/dma-mapping.h>. If we need to differentiate them for some architectures, we can move the generic definitions to <asm-generic/dma-mapping.h>. Add some comments to the helpers. The concept is quite similar to the DMA-API of Linux kernel. Drivers are agnostic about what is going on behind the scene. Just call dma_map_single() before the DMA, and dma_unmap_single() after it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
64 lines
1.8 KiB
C
64 lines
1.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_DMA_MAPPING_H
|
|
#define _LINUX_DMA_MAPPING_H
|
|
|
|
#include <linux/dma-direction.h>
|
|
#include <linux/types.h>
|
|
#include <asm/dma-mapping.h>
|
|
#include <cpu_func.h>
|
|
|
|
#define dma_mapping_error(x, y) 0
|
|
|
|
/**
|
|
* Map a buffer to make it available to the DMA device
|
|
*
|
|
* Linux-like DMA API that is intended to be used from drivers. This hides the
|
|
* underlying cache operation from drivers. Call this before starting the DMA
|
|
* transfer. In most of architectures in U-Boot, the virtual address matches to
|
|
* the physical address (but we have exceptions like sandbox). U-Boot does not
|
|
* support iommu at the driver level, so it also matches to the DMA address.
|
|
* Hence, this helper currently just performs the cache operation, then returns
|
|
* straight-mapped dma_address, which is intended to be set to the register of
|
|
* the DMA device.
|
|
*
|
|
* @vaddr: address of the buffer
|
|
* @len: length of the buffer
|
|
* @dir: the direction of DMA
|
|
*/
|
|
static inline dma_addr_t dma_map_single(void *vaddr, size_t len,
|
|
enum dma_data_direction dir)
|
|
{
|
|
unsigned long addr = (unsigned long)vaddr;
|
|
|
|
len = ALIGN(len, ARCH_DMA_MINALIGN);
|
|
|
|
if (dir == DMA_FROM_DEVICE)
|
|
invalidate_dcache_range(addr, addr + len);
|
|
else
|
|
flush_dcache_range(addr, addr + len);
|
|
|
|
return addr;
|
|
}
|
|
|
|
/**
|
|
* Unmap a buffer to make it available to CPU
|
|
*
|
|
* Linux-like DMA API that is intended to be used from drivers. This hides the
|
|
* underlying cache operation from drivers. Call this after finishin the DMA
|
|
* transfer.
|
|
*
|
|
* @addr: DMA address
|
|
* @len: length of the buffer
|
|
* @dir: the direction of DMA
|
|
*/
|
|
static inline void dma_unmap_single(dma_addr_t addr, size_t len,
|
|
enum dma_data_direction dir)
|
|
{
|
|
len = ALIGN(len, ARCH_DMA_MINALIGN);
|
|
|
|
if (dir != DMA_TO_DEVICE)
|
|
invalidate_dcache_range(addr, addr + len);
|
|
}
|
|
|
|
#endif
|