[PATCH 03/12] pci-p2p: Add PCI p2pmem dma mappings to adjust the bus offset
From: Logan Gunthorpe <logang@deltatee.com>
Date: 2018-01-04 19:06:09
Also in:
linux-nvme, linux-pci, linux-rdma, lkml, nvdimm
Subsystem:
memory hot(un)plug, pci subsystem, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Bjorn Helgaas, Linus Torvalds
The DMA address used when mapping PCI P2P memory must be the PCI bus address. Thus, introduce pci_p2pmem_[un]map_sg() to map the correct addresses when using P2P memory. For this, we assume that an SGL passed to these functions contain all p2p memory or no p2p memory. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> --- drivers/pci/p2p.c | 43 +++++++++++++++++++++++++++++++++++++++++++ include/linux/memremap.h | 1 + include/linux/pci-p2p.h | 9 +++++++++ 3 files changed, 53 insertions(+)
diff --git a/drivers/pci/p2p.c b/drivers/pci/p2p.c
index 03330c7b5e6d..87cec87b02e3 100644
--- a/drivers/pci/p2p.c
+++ b/drivers/pci/p2p.c@@ -184,6 +184,8 @@ int pci_p2pmem_add_resource(struct pci_dev *pdev, int bar, size_t size, pgmap->res.end = pgmap->res.start + size - 1; pgmap->ref = &pdev->p2p->devmap_ref; pgmap->type = MEMORY_DEVICE_PCI_P2P; + pgmap->pci_p2p_bus_offset = pci_bus_address(pdev, bar) - + pci_resource_start(pdev, bar); addr = devm_memremap_pages(&pdev->dev, pgmap); if (IS_ERR(addr))
@@ -598,3 +600,44 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) pdev->p2p->published = publish; } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); + +/* + * pci_p2pmem_map_sg - map a pci p2p sg for dma + * @sg:scatter list to map + * @nents:elements in the scatter list + * + * Returns the number of sgls mapped + */ +int pci_p2pmem_map_sg(struct scatterlist *sg, int nents) +{ + struct dev_pagemap *pgmap; + struct scatterlist *s; + phys_addr_t paddr; + int i; + + for_each_sg(sg, s, nents, i) { + pgmap = sg_page(s)->pgmap; + paddr = sg_phys(s); + + s->dma_address = paddr - pgmap->pci_p2p_bus_offset; + sg_dma_len(s) = s->length; + } + + return nents; +} +EXPORT_SYMBOL_GPL(pci_p2pmem_map_sg); + +/** + * pci_p2pmem_unmap_sg - unmap a pci p2p sg for dma + * @sg:scatter list to map + * @nents:elements in the scatter list + */ +void pci_p2pmem_unmap_sg(struct scatterlist *sg, int nents) +{ + struct scatterlist *s; + int i; + + for_each_sg(sg, s, nents, i) + dma_mark_clean(phys_to_virt(sg_phys(s)), sg_dma_len(s)); +} +EXPORT_SYMBOL_GPL(pci_p2pmem_unmap_sg);
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index c17a6d167d48..a792f87b9dc3 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h@@ -125,6 +125,7 @@ struct dev_pagemap { struct device *dev; void *data; enum memory_type type; + u64 pci_p2p_bus_offset; }; #ifdef CONFIG_ZONE_DEVICE
diff --git a/include/linux/pci-p2p.h b/include/linux/pci-p2p.h
index f811c97a5886..154c39905fc9 100644
--- a/include/linux/pci-p2p.h
+++ b/include/linux/pci-p2p.h@@ -34,6 +34,8 @@ int pci_p2pmem_alloc_sgl(struct pci_dev *pdev, struct scatterlist **sgl, void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl, unsigned int nents); void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); +int pci_p2pmem_map_sg(struct scatterlist *sg, int nents); +void pci_p2pmem_unmap_sg(struct scatterlist *sg, int nents); #else /* CONFIG_PCI_P2P */ static inline int pci_p2pmem_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset)
@@ -81,5 +83,12 @@ 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 int pci_p2pmem_map_sg(struct scatterlist *sg, int nents) +{ + return -ENODEV; +} +static inline void pci_p2pmem_unmap_sg(struct scatterlist *sg, int nents) +{ +} #endif /* CONFIG_PCI_P2P */ #endif /* _LINUX_PCI_P2P_H */
--
2.11.0