Merge branch 'pci/aspm'

  - Use Latency Tolerance Reporting if already enabled by platform (Bjorn
    Helgaas)

  - Save/restore LTR info for suspend/resume (Bjorn Helgaas)

* pci/aspm:
  PCI/ASPM: Save LTR Capability for suspend/resume
  PCI/ASPM: Use LTR if already enabled by platform

1 files changed, 23 insertions, 13 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 43e6583417ce..1078195f244a 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2069,11 +2069,8 @@ static void pci_configure_ltr(struct pci_dev *dev)
 {
 #ifdef CONFIG_PCIEASPM
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
-	u32 cap;
 	struct pci_dev *bridge;
-
-	if (!host->native_ltr)
-		return;
+	u32 cap, ctl;
 
 	if (!pci_is_pcie(dev))
 		return;
@@ -2082,22 +2079,35 @@ static void pci_configure_ltr(struct pci_dev *dev)
 	if (!(cap & PCI_EXP_DEVCAP2_LTR))
 		return;
 
-	/*
-	 * Software must not enable LTR in an Endpoint unless the Root
-	 * Complex and all intermediate Switches indicate support for LTR.
-	 * PCIe r3.1, sec 6.18.
-	 */
-	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
-		dev->ltr_path = 1;
-	else {
+	pcie_capability_read_dword(dev, PCI_EXP_DEVCTL2, &ctl);
+	if (ctl & PCI_EXP_DEVCTL2_LTR_EN) {
+		if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
+			dev->ltr_path = 1;
+			return;
+		}
+
 		bridge = pci_upstream_bridge(dev);
 		if (bridge && bridge->ltr_path)
 			dev->ltr_path = 1;
+
+		return;
 	}
 
-	if (dev->ltr_path)
+	if (!host->native_ltr)
+		return;
+
+	/*
+	 * Software must not enable LTR in an Endpoint unless the Root
+	 * Complex and all intermediate Switches indicate support for LTR.
+	 * PCIe r4.0, sec 6.18.
+	 */
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
+	    ((bridge = pci_upstream_bridge(dev)) &&
+	      bridge->ltr_path)) {
 		pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
 					 PCI_EXP_DEVCTL2_LTR_EN);
+		dev->ltr_path = 1;
+	}
 #endif
 }