linux/lib/dma-noncoherent.c
Christoph Hellwig 782e6769c0 dma-mapping: provide a generic dma-noncoherent implementation
Add a new dma_map_ops implementation that uses dma-direct for the
address mapping of streaming mappings, and which requires arch-specific
implemenations of coherent allocate/free.

Architectures have to provide flushing helpers to ownership trasnfers
to the device and/or CPU, and can provide optional implementations of
the coherent mmap functionality, and the cache_flush routines for
non-coherent long term allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
2018-05-19 08:46:12 +02:00

103 lines
3.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2018 Christoph Hellwig.
*
* DMA operations that map physical memory directly without providing cache
* coherence.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/scatterlist.h>
static void dma_noncoherent_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
arch_sync_dma_for_device(dev, dma_to_phys(dev, addr), size, dir);
}
static void dma_noncoherent_sync_sg_for_device(struct device *dev,
struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nents, i)
arch_sync_dma_for_device(dev, sg_phys(sg), sg->length, dir);
}
static dma_addr_t dma_noncoherent_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
dma_addr_t addr;
addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
if (!dma_mapping_error(dev, addr) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
arch_sync_dma_for_device(dev, page_to_phys(page) + offset,
size, dir);
return addr;
}
static int dma_noncoherent_map_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
nents = dma_direct_map_sg(dev, sgl, nents, dir, attrs);
if (nents > 0 && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_noncoherent_sync_sg_for_device(dev, sgl, nents, dir);
return nents;
}
#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
static void dma_noncoherent_sync_single_for_cpu(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
arch_sync_dma_for_cpu(dev, dma_to_phys(dev, addr), size, dir);
}
static void dma_noncoherent_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sgl, int nents, enum dma_data_direction dir)
{
struct scatterlist *sg;
int i;
for_each_sg(sgl, sg, nents, i)
arch_sync_dma_for_cpu(dev, sg_phys(sg), sg->length, dir);
}
static void dma_noncoherent_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_noncoherent_sync_single_for_cpu(dev, addr, size, dir);
}
static void dma_noncoherent_unmap_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
dma_noncoherent_sync_sg_for_cpu(dev, sgl, nents, dir);
}
#endif
const struct dma_map_ops dma_noncoherent_ops = {
.alloc = arch_dma_alloc,
.free = arch_dma_free,
.mmap = arch_dma_mmap,
.sync_single_for_device = dma_noncoherent_sync_single_for_device,
.sync_sg_for_device = dma_noncoherent_sync_sg_for_device,
.map_page = dma_noncoherent_map_page,
.map_sg = dma_noncoherent_map_sg,
#ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU
.sync_single_for_cpu = dma_noncoherent_sync_single_for_cpu,
.sync_sg_for_cpu = dma_noncoherent_sync_sg_for_cpu,
.unmap_page = dma_noncoherent_unmap_page,
.unmap_sg = dma_noncoherent_unmap_sg,
#endif
.dma_supported = dma_direct_supported,
.mapping_error = dma_direct_mapping_error,
.cache_sync = arch_dma_cache_sync,
};
EXPORT_SYMBOL(dma_noncoherent_ops);