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MIPS: remove mips_swiotlb_ops 

mips_swiotlb_ops differs from the generic swiotlb_dma_ops only in that
it contains a mb() barrier after each operations that maps or syncs
dma memory to the device.

The dma operations are defined to not be memory barriers, but instead
the write* operations to kick the DMA off are supposed to contain them.

For mips this handled by war_io_reorder_wmb(), which evaluates to the
stronger wmb() instead of the pure compiler barrier barrier() for
just those platforms that use swiotlb, so I think we are covered
properly.

[paul.burton@mips.com:
  - Include linux/swiotlb.h to fix build failures for configs with
    CONFIG_SWIOTLB=y.]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20038/
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-mips@linux-mips.org
Cc: iommu@lists.linux-foundation.org
Cc: linux-kernel@vger.kernel.org
This commit is contained in:
Christoph Hellwig 2018-07-27 19:26:06 +02:00 committed by Paul Burton
parent d4da0e97ba
commit a999933db9
No known key found for this signature in database
GPG Key ID: 3EA79FACB57500DD
3 changed files with 3 additions and 64 deletions
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5
arch/mips/include/asm/dma-mapping.h
View File

@ -2,15 +2,16 @@
#ifndef _ASM_DMA_MAPPING_H
#define _ASM_DMA_MAPPING_H
#include <linux/swiotlb.h>
extern const struct dma_map_ops jazz_dma_ops;
extern const struct dma_map_ops mips_swiotlb_ops;
static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
{
#if defined(CONFIG_MACH_JAZZ)
return &jazz_dma_ops;
#elif defined(CONFIG_SWIOTLB)
return &mips_swiotlb_ops;
return &swiotlb_dma_ops;
#elif defined(CONFIG_DMA_NONCOHERENT_OPS)
return &dma_noncoherent_ops;
#else

1
arch/mips/mm/Makefile
View File

@ -18,7 +18,6 @@ obj-$(CONFIG_64BIT) += pgtable-64.o
obj-$(CONFIG_HIGHMEM) += highmem.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
obj-$(CONFIG_DMA_NONCOHERENT) += dma-noncoherent.o
obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o
obj-$(CONFIG_CPU_R4K_CACHE_TLB) += c-r4k.o cex-gen.o tlb-r4k.o
obj-$(CONFIG_CPU_R3000) += c-r3k.o tlb-r3k.o

61
arch/mips/mm/dma-swiotlb.c
View File

@ -1,61 +0,0 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/dma-mapping.h>
#include <linux/swiotlb.h>
static void *mips_swiotlb_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
void *ret = swiotlb_alloc(dev, size, dma_handle, gfp, attrs);
mb();
return ret;
}
static dma_addr_t mips_swiotlb_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 daddr = swiotlb_map_page(dev, page, offset, size,
dir, attrs);
mb();
return daddr;
}
static int mips_swiotlb_map_sg(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
int r = swiotlb_map_sg_attrs(dev, sg, nents, dir, attrs);
mb();
return r;
}
static void mips_swiotlb_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
{
swiotlb_sync_single_for_device(dev, dma_handle, size, dir);
mb();
}
static void mips_swiotlb_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nents, enum dma_data_direction dir)
{
swiotlb_sync_sg_for_device(dev, sg, nents, dir);
mb();
}
const struct dma_map_ops mips_swiotlb_ops = {
.alloc = mips_swiotlb_alloc,
.free = swiotlb_free,
.map_page = mips_swiotlb_map_page,
.unmap_page = swiotlb_unmap_page,
.map_sg = mips_swiotlb_map_sg,
.unmap_sg = swiotlb_unmap_sg_attrs,
.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
.sync_single_for_device = mips_swiotlb_sync_single_for_device,
.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
.sync_sg_for_device = mips_swiotlb_sync_sg_for_device,
.mapping_error = swiotlb_dma_mapping_error,
.dma_supported = swiotlb_dma_supported,
};
EXPORT_SYMBOL(mips_swiotlb_ops);