linux/kernel/dma/dummy.c
Christoph Hellwig 0a0f0d8be7 dma-mapping: split <linux/dma-mapping.h>
Split out all the bits that are purely for dma_map_ops implementations
and related code into a new <linux/dma-map-ops.h> header so that they
don't get pulled into all the drivers.  That also means the architecture
specific <asm/dma-mapping.h> is not pulled in by <linux/dma-mapping.h>
any more, which leads to a missing includes that were pulled in by the
x86 or arm versions in a few not overly portable drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2020-10-06 07:07:03 +02:00

39 lines
940 B
C

// SPDX-License-Identifier: GPL-2.0
/*
* Dummy DMA ops that always fail.
*/
#include <linux/dma-map-ops.h>
static int dma_dummy_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
return -ENXIO;
}
static dma_addr_t dma_dummy_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
return DMA_MAPPING_ERROR;
}
static int dma_dummy_map_sg(struct device *dev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir,
unsigned long attrs)
{
return 0;
}
static int dma_dummy_supported(struct device *hwdev, u64 mask)
{
return 0;
}
const struct dma_map_ops dma_dummy_ops = {
.mmap = dma_dummy_mmap,
.map_page = dma_dummy_map_page,
.map_sg = dma_dummy_map_sg,
.dma_supported = dma_dummy_supported,
};