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-rw-r--r--drivers/pci/p2pdma.c43
-rw-r--r--include/linux/memremap.h1
-rw-r--r--include/linux/pci-p2pdma.h7
3 files changed, 51 insertions, 0 deletions
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index a8d484ddc5ad..09b3146c145c 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -194,6 +194,8 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
pgmap->res.flags = pci_resource_flags(pdev, bar);
pgmap->ref = &pdev->p2pdma->devmap_ref;
pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
+ pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) -
+ pci_resource_start(pdev, bar);
addr = devm_memremap_pages(&pdev->dev, pgmap);
if (IS_ERR(addr)) {
@@ -678,3 +680,44 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
pdev->p2pdma->p2pmem_published = publish;
}
EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
+
+/**
+ * pci_p2pdma_map_sg - map a PCI peer-to-peer scatterlist for DMA
+ * @dev: device doing the DMA request
+ * @sg: scatter list to map
+ * @nents: elements in the scatterlist
+ * @dir: DMA direction
+ *
+ * Scatterlists mapped with this function should not be unmapped in any way.
+ *
+ * Returns the number of SG entries mapped or 0 on error.
+ */
+int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+ enum dma_data_direction dir)
+{
+ struct dev_pagemap *pgmap;
+ struct scatterlist *s;
+ phys_addr_t paddr;
+ int i;
+
+ /*
+ * p2pdma mappings are not compatible with devices that use
+ * dma_virt_ops. If the upper layers do the right thing
+ * this should never happen because it will be prevented
+ * by the check in pci_p2pdma_add_client()
+ */
+ if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) &&
+ dev->dma_ops == &dma_virt_ops))
+ return 0;
+
+ for_each_sg(sg, s, nents, i) {
+ pgmap = sg_page(s)->pgmap;
+ paddr = sg_phys(s);
+
+ s->dma_address = paddr - pgmap->pci_p2pdma_bus_offset;
+ sg_dma_len(s) = s->length;
+ }
+
+ return nents;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg);
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 9553370ebdad..0ac69ddf5fc4 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_p2pdma_bus_offset;
};
#ifdef CONFIG_ZONE_DEVICE
diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
index 7bdaacfd5892..b6dfb6dc2e53 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -30,6 +30,8 @@ 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);
+int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
+ enum dma_data_direction dir);
#else /* CONFIG_PCI_P2PDMA */
static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar,
size_t size, u64 offset)
@@ -75,6 +77,11 @@ 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 int pci_p2pdma_map_sg(struct device *dev,
+ struct scatterlist *sg, int nents, enum dma_data_direction dir)
+{
+ return 0;
+}
#endif /* CONFIG_PCI_P2PDMA */