static int amd_poll_link(struct amd_ntb_dev *ndev)
{
void __iomem *mmio = ndev->peer_mmio;
+ struct pci_dev *pdev = NULL;
+ struct pci_dev *pci_swds = NULL;
+ struct pci_dev *pci_swus = NULL;
u32 reg, stat;
int rc;
ndev->cntl_sta = reg;
- rc = pcie_capability_read_dword(ndev->ntb.pdev,
- PCI_EXP_LNKCTL, &stat);
- if (rc)
+ if (ndev->ntb.topo == NTB_TOPO_SEC) {
+ /* Locate the pointer to Downstream Switch for this device */
+ pci_swds = pci_upstream_bridge(ndev->ntb.pdev);
+ if (pci_swds) {
+ /*
+ * Locate the pointer to Upstream Switch for
+ * the Downstream Switch.
+ */
+ pci_swus = pci_upstream_bridge(pci_swds);
+ if (pci_swus) {
+ rc = pcie_capability_read_dword(pci_swus,
+ PCI_EXP_LNKCTL,
+ &stat);
+ if (rc)
+ return 0;
+ } else {
+ return 0;
+ }
+ } else {
+ return 0;
+ }
+ } else if (ndev->ntb.topo == NTB_TOPO_PRI) {
+ /*
+ * For NTB primary, we simply read the Link Status and control
+ * register of the NTB device itself.
+ */
+ pdev = ndev->ntb.pdev;
+ rc = pcie_capability_read_dword(pdev, PCI_EXP_LNKCTL, &stat);
+ if (rc)
+ return 0;
+ } else {
+ /* Catch all for everything else */
return 0;
+ }
+
ndev->lnk_sta = stat;
return 1;