diff options
| author | Logan Gunthorpe <logang@deltatee.com> | 2022-07-08 10:50:56 -0600 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2022-07-26 07:27:47 -0400 |
| commit | f02ad36d4f76645e7e1c21f572260e9a2e61c26b (patch) | |
| tree | 0e46523b735822b5db0e63e4afb0af0841a1e275 /kernel/dma/direct.h | |
| parent | 7c2645a2a30a45d3dc4c98b315a51be44ec69a67 (diff) | |
dma-direct: support PCI P2PDMA pages in dma-direct map_sg
Add PCI P2PDMA support for dma_direct_map_sg() so that it can map
PCI P2PDMA pages directly without a hack in the callers. This allows
for heterogeneous SGLs that contain both P2PDMA and regular pages.
A P2PDMA page may have three possible outcomes when being mapped:
1) If the data path between the two devices doesn't go through the
root port, then it should be mapped with a PCI bus address
2) If the data path goes through the host bridge, it should be mapped
normally, as though it were a CPU physical address
3) It is not possible for the two devices to communicate and thus
the mapping operation should fail (and it will return -EREMOTEIO).
SGL segments that contain PCI bus addresses are marked with
sg_dma_mark_pci_p2pdma() and are ignored when unmapped.
P2PDMA mappings are also failed if swiotlb needs to be used on the
mapping.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'kernel/dma/direct.h')
| -rw-r--r-- | kernel/dma/direct.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/dma/direct.h b/kernel/dma/direct.h index a78c0ba70645..e38ffc5e6bdd 100644 --- a/kernel/dma/direct.h +++ b/kernel/dma/direct.h @@ -8,6 +8,7 @@ #define _KERNEL_DMA_DIRECT_H #include <linux/dma-direct.h> +#include <linux/memremap.h> int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr, size_t size, @@ -87,10 +88,15 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev, phys_addr_t phys = page_to_phys(page) + offset; dma_addr_t dma_addr = phys_to_dma(dev, phys); - if (is_swiotlb_force_bounce(dev)) + if (is_swiotlb_force_bounce(dev)) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; return swiotlb_map(dev, phys, size, dir, attrs); + } if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + if (is_pci_p2pdma_page(page)) + return DMA_MAPPING_ERROR; if (is_swiotlb_active(dev)) return swiotlb_map(dev, phys, size, dir, attrs); |