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swiotlb: Introduce swiotlb_max_mapping_size() 

The function returns the maximum size that can be remapped
by the SWIOTLB implementation. This function will be later
exposed to users through the DMA-API.

Cc: stable@vger.kernel.org
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
hifive-unleashed-5.1
Joerg Roedel 2019-02-07 12:59:13 +01:00 committed by Michael S. Tsirkin
parent 1c163f4c7b
commit abe420bfae
2 changed files with 10 additions and 0 deletions
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5
include/linux/swiotlb.h
View File

@ -76,6 +76,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
size_t size, enum dma_data_direction dir, unsigned long attrs);
void __init swiotlb_exit(void);
unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
#else
#define swiotlb_force SWIOTLB_NO_FORCE
static inline bool is_swiotlb_buffer(phys_addr_t paddr)
@ -95,6 +96,10 @@ static inline unsigned int swiotlb_max_segment(void)
{
return 0;
}
static inline size_t swiotlb_max_mapping_size(struct device *dev)
{
return SIZE_MAX;
}
#endif /* CONFIG_SWIOTLB */
extern void swiotlb_print_info(void);

5
kernel/dma/swiotlb.c
View File

@ -662,3 +662,8 @@ swiotlb_dma_supported(struct device *hwdev, u64 mask)
{
return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask;
}
size_t swiotlb_max_mapping_size(struct device *dev)
{
return ((size_t)1 << IO_TLB_SHIFT) * IO_TLB_SEGSIZE;
}