PCI/ASPM: Move pci_configure_ltr() to aspm.c

The Latency Tolerance Reporting (LTR) mechanism supports the ASPM L1.2
state and is only configured when CONFIG_PCIEASPM is set.

Move pci_configure_ltr() and pci_bridge_reconfigure_ltr() into aspm.c since
they only build when CONFIG_PCIEASPM is set.  No functional change
intended.
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20240128233212.1139663-2-david.e.box@linux.intel.com
[bhelgaas: commit log, split build change from function moves]
Link: https://lore.kernel.org/r/20240223205851.114931-2-helgaas@kernel.orgSigned-off-by: David E. Box <david.e.box@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -1626,24 +1626,6 @@ static int pci_save_pcie_state(struct pci_dev *dev)
 	return 0;
 }
 
-void pci_bridge_reconfigure_ltr(struct pci_dev *dev)
-{
-#ifdef CONFIG_PCIEASPM
-	struct pci_dev *bridge;
-	u32 ctl;
-
-	bridge = pci_upstream_bridge(dev);
-	if (bridge && bridge->ltr_path) {
-		pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2, &ctl);
-		if (!(ctl & PCI_EXP_DEVCTL2_LTR_EN)) {
-			pci_dbg(bridge, "re-enabling LTR\n");
-			pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
-						 PCI_EXP_DEVCTL2_LTR_EN);
-		}
-	}
-#endif
-}
-
 static void pci_restore_pcie_state(struct pci_dev *dev)
 {
 	int i = 0;

drivers/pci/pci.h

@@ -97,7 +97,6 @@ void pci_msi_init(struct pci_dev *dev);
 void pci_msix_init(struct pci_dev *dev);
 bool pci_bridge_d3_possible(struct pci_dev *dev);
 void pci_bridge_d3_update(struct pci_dev *dev);
-void pci_bridge_reconfigure_ltr(struct pci_dev *dev);
 int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type);
 
 static inline void pci_wakeup_event(struct pci_dev *dev)
@@ -573,11 +572,15 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev);
 void pcie_aspm_exit_link_state(struct pci_dev *pdev);
 void pcie_aspm_pm_state_change(struct pci_dev *pdev);
 void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
+void pci_configure_ltr(struct pci_dev *pdev);
+void pci_bridge_reconfigure_ltr(struct pci_dev *pdev);
 #else
 static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
 static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
 static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
+static inline void pci_configure_ltr(struct pci_dev *pdev) { }
+static inline void pci_bridge_reconfigure_ltr(struct pci_dev *pdev) { }
 #endif
 
 #ifdef CONFIG_PCIE_ECRC

drivers/pci/pcie/aspm.c

@@ -938,6 +938,81 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
 	up_read(&pci_bus_sem);
 }
 
+void pci_bridge_reconfigure_ltr(struct pci_dev *pdev)
+{
+	struct pci_dev *bridge;
+	u32 ctl;
+
+	bridge = pci_upstream_bridge(pdev);
+	if (bridge && bridge->ltr_path) {
+		pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2, &ctl);
+		if (!(ctl & PCI_EXP_DEVCTL2_LTR_EN)) {
+			pci_dbg(bridge, "re-enabling LTR\n");
+			pcie_capability_set_word(bridge, PCI_EXP_DEVCTL2,
+						 PCI_EXP_DEVCTL2_LTR_EN);
+		}
+	}
+}
+
+void pci_configure_ltr(struct pci_dev *pdev)
+{
+	struct pci_host_bridge *host = pci_find_host_bridge(pdev->bus);
+	struct pci_dev *bridge;
+	u32 cap, ctl;
+
+	if (!pci_is_pcie(pdev))
+		return;
+
+	/* Read L1 PM substate capabilities */
+	pdev->l1ss = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS);
+
+	pcie_capability_read_dword(pdev, PCI_EXP_DEVCAP2, &cap);
+	if (!(cap & PCI_EXP_DEVCAP2_LTR))
+		return;
+
+	pcie_capability_read_dword(pdev, PCI_EXP_DEVCTL2, &ctl);
+	if (ctl & PCI_EXP_DEVCTL2_LTR_EN) {
+		if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT) {
+			pdev->ltr_path = 1;
+			return;
+		}
+
+		bridge = pci_upstream_bridge(pdev);
+		if (bridge && bridge->ltr_path)
+			pdev->ltr_path = 1;
+
+		return;
+	}
+
+	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(pdev) == PCI_EXP_TYPE_ROOT_PORT) {
+		pcie_capability_set_word(pdev, PCI_EXP_DEVCTL2,
+					 PCI_EXP_DEVCTL2_LTR_EN);
+		pdev->ltr_path = 1;
+		return;
+	}
+
+	/*
+	 * If we're configuring a hot-added device, LTR was likely
+	 * disabled in the upstream bridge, so re-enable it before enabling
+	 * it in the new device.
+	 */
+	bridge = pci_upstream_bridge(pdev);
+	if (bridge && bridge->ltr_path) {
+		pci_bridge_reconfigure_ltr(pdev);
+		pcie_capability_set_word(pdev, PCI_EXP_DEVCTL2,
+					 PCI_EXP_DEVCTL2_LTR_EN);
+		pdev->ltr_path = 1;
+	}
+}
+
 /* Recheck latencies and update aspm_capable for links under the root */
 static void pcie_update_aspm_capable(struct pcie_link_state *root)
 {

drivers/pci/probe.c

@@ -2209,67 +2209,6 @@ static void pci_configure_relaxed_ordering(struct pci_dev *dev)
 	}
 }
 
-static void pci_configure_ltr(struct pci_dev *dev)
-{
-#ifdef CONFIG_PCIEASPM
-	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
-	struct pci_dev *bridge;
-	u32 cap, ctl;
-
-	if (!pci_is_pcie(dev))
-		return;
-
-	/* Read L1 PM substate capabilities */
-	dev->l1ss = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_L1SS);
-
-	pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
-	if (!(cap & PCI_EXP_DEVCAP2_LTR))
-		return;
-
-	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 (!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) {
-		pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
-					 PCI_EXP_DEVCTL2_LTR_EN);
-		dev->ltr_path = 1;
-		return;
-	}
-
-	/*
-	 * If we're configuring a hot-added device, LTR was likely
-	 * disabled in the upstream bridge, so re-enable it before enabling
-	 * it in the new device.
-	 */
-	bridge = pci_upstream_bridge(dev);
-	if (bridge && bridge->ltr_path) {
-		pci_bridge_reconfigure_ltr(dev);
-		pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
-					 PCI_EXP_DEVCTL2_LTR_EN);
-		dev->ltr_path = 1;
-	}
-#endif
-}
-
 static void pci_configure_eetlp_prefix(struct pci_dev *dev)
 {
 #ifdef CONFIG_PCI_PASID