pci_p2pdma_map_type() will be needed by the dma-iommu map_sg implementation because it will need to determine the mapping type ahead of actually doing the mapping to create the actual iommu mapping. Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> --- drivers/pci/p2pdma.c | 24 +++++++++++++--------- include/linux/pci-p2pdma.h | 41 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+), 9 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 6c2057cd3f37..0568604fd8b4 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -20,13 +20,6 @@ #include <linux/seq_buf.h> #include <linux/xarray.h> -enum pci_p2pdma_map_type { - PCI_P2PDMA_MAP_UNKNOWN = 0, - PCI_P2PDMA_MAP_NOT_SUPPORTED, - PCI_P2PDMA_MAP_BUS_ADDR, - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, -}; - struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; @@ -844,8 +837,21 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, - struct device *dev) +/** + * pci_p2pdma_map_type - return the type of mapping that should be used for + * a given device and pgmap + * @pgmap: the pagemap of a page to determine the mapping type for + * @dev: device that is mapping the page + * + * Returns one of: + * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done + * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done normally + * using the CPU physical address (in dma-direct) or an IOVA + * mapping for the IOMMU. + */ +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, + struct device *dev) { struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; enum pci_p2pdma_map_type ret; diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 8318a97c9c61..caac2d023f8f 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -16,6 +16,40 @@ struct block_device; struct scatterlist; +enum pci_p2pdma_map_type { + /* + * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping + * type hasn't been calculated yet. Functions that return this enum + * never return this value. + */ + PCI_P2PDMA_MAP_UNKNOWN = 0, + + /* + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will + * traverse the host bridge and the host bridge is not in the + * whitelist. DMA Mapping routines should return an error when + * this is returned. + */ + PCI_P2PDMA_MAP_NOT_SUPPORTED, + + /* + * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to + * eachother directly through a PCI switch and the transaction will + * not traverse the host bridge. Such a mapping should program + * the DMA engine with PCI bus addresses. + */ + PCI_P2PDMA_MAP_BUS_ADDR, + + /* + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk + * to eachother, but the transaction traverses a host bridge on the + * whitelist. In this case, a normal mapping either with CPU physical + * addresses (in the case of dma-direct) or IOVA addresses (in the + * case of IOMMUs) should be used to program the DMA engine. + */ + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, +}; + #ifdef CONFIG_PCI_P2PDMA int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset); @@ -30,6 +64,8 @@ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, unsigned int *nents, u32 length); void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, + struct device *dev); int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs); void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, @@ -83,6 +119,11 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev, static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) { } +static inline enum pci_p2pdma_map_type +pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev) +{ + return PCI_P2PDMA_MAP_NOT_SUPPORTED; +} static inline int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs) -- 2.20.1