1 files changed, 66 insertions, 0 deletions

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index 24d2b7eff59b..e499fe78756b 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -17,6 +17,7 @@
 #include <linux/module.h>
 #include <linux/delay.h>
 #include <linux/property.h>
+#include <linux/platform_data/x86/apple.h>
 
 #include "nhi.h"
 #include "nhi_regs.h"
@@ -1069,6 +1070,69 @@ static bool nhi_imr_valid(struct pci_dev *pdev)
 	return true;
 }
 
+/*
+ * During suspend the Thunderbolt controller is reset and all PCIe
+ * tunnels are lost. The NHI driver will try to reestablish all tunnels
+ * during resume. This adds device links between the tunneled PCIe
+ * downstream ports and the NHI so that the device core will make sure
+ * NHI is resumed first before the rest.
+ */
+static void tb_apple_add_links(struct tb_nhi *nhi)
+{
+	struct pci_dev *upstream, *pdev;
+
+	if (!x86_apple_machine)
+		return;
+
+	switch (nhi->pdev->device) {
+	case PCI_DEVICE_ID_INTEL_LIGHT_RIDGE:
+	case PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C:
+	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_2C_NHI:
+	case PCI_DEVICE_ID_INTEL_FALCON_RIDGE_4C_NHI:
+		break;
+	default:
+		return;
+	}
+
+	upstream = pci_upstream_bridge(nhi->pdev);
+	while (upstream) {
+		if (!pci_is_pcie(upstream))
+			return;
+		if (pci_pcie_type(upstream) == PCI_EXP_TYPE_UPSTREAM)
+			break;
+		upstream = pci_upstream_bridge(upstream);
+	}
+
+	if (!upstream)
+		return;
+
+	/*
+	 * For each hotplug downstream port, create add device link
+	 * back to NHI so that PCIe tunnels can be re-established after
+	 * sleep.
+	 */
+	for_each_pci_bridge(pdev, upstream->subordinate) {
+		const struct device_link *link;
+
+		if (!pci_is_pcie(pdev))
+			continue;
+		if (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM ||
+		    !pdev->is_hotplug_bridge)
+			continue;
+
+		link = device_link_add(&pdev->dev, &nhi->pdev->dev,
+				       DL_FLAG_AUTOREMOVE_SUPPLIER |
+				       DL_FLAG_PM_RUNTIME);
+		if (link) {
+			dev_dbg(&nhi->pdev->dev, "created link from %s\n",
+				dev_name(&pdev->dev));
+		} else {
+			dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n",
+				 dev_name(&pdev->dev));
+		}
+	}
+}
+
 static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
 	struct tb_nhi *nhi;
@@ -1134,6 +1198,8 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 			return res;
 	}
 
+	tb_apple_add_links(nhi);
+
 	tb = icm_probe(nhi);
 	if (!tb)
 		tb = tb_probe(nhi);