PCI: endpoint: pci-epf-vntb: Implement .get_dma_dev()

When vNTB is used as a PCI endpoint function, the NTB device is backed
by a virtual PCI function. For DMA API allocations and mappings, NTB
clients must use the device that is associated with the IOMMU domain.

Implement ntb_dev_ops->get_dma_dev() for pci-epf-vntb and return the EPC
parent device.

Suggested-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260306031443.1911860-4-den@valinux.co.jp

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 80535352896738321be2c8701da555549e28ce29..2256c3062b1ae01be754e5afe9d93d2421a60018 100644 (file)
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -1428,6 +1428,14 @@ static int vntb_epf_link_disable(struct ntb_dev *ntb)
        return 0;
 }
 
+static struct device *vntb_epf_get_dma_dev(struct ntb_dev *ndev)
+{
+       struct epf_ntb *ntb = ntb_ndev(ndev);
+       struct pci_epc *epc = ntb->epf->epc;
+
+       return epc->dev.parent;
+}
+
 static const struct ntb_dev_ops vntb_epf_ops = {
        .mw_count               = vntb_epf_mw_count,
        .spad_count             = vntb_epf_spad_count,
@@ -1449,6 +1457,7 @@ static const struct ntb_dev_ops vntb_epf_ops = {
        .db_clear_mask          = vntb_epf_db_clear_mask,
        .db_clear               = vntb_epf_db_clear,
        .link_disable           = vntb_epf_link_disable,
+       .get_dma_dev            = vntb_epf_get_dma_dev,
 };
 
 static int pci_vntb_probe(struct pci_dev *pdev, const struct pci_device_id *id)