[1/2] PCI/PM: Revert "PCI/PM: Drop unused runtime PM support code for PCIe ports"

diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index be35da2..1e4a562 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -93,6 +93,71 @@  static int pcie_port_resume_noirq(struct device *dev)
 	return 0;
 }
 
+struct d3cold_info {
+	bool no_d3cold;
+	unsigned int d3cold_delay;
+};
+
+static int pci_dev_d3cold_info(struct pci_dev *pdev, void *data)
+{
+	struct d3cold_info *info = data;
+
+	info->d3cold_delay = max_t(unsigned int, pdev->d3cold_delay,
+				   info->d3cold_delay);
+	if (pdev->no_d3cold)
+		info->no_d3cold = true;
+	return 0;
+}
+
+static int pcie_port_runtime_suspend(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct d3cold_info d3cold_info = {
+		.no_d3cold	= false,
+		.d3cold_delay	= PCI_PM_D3_WAIT,
+	};
+
+	/*
+	 * If any subordinate device disable D3cold, we should not put
+	 * the port into D3cold.  The D3cold delay of port should be
+	 * the max of that of all subordinate devices.
+	 */
+	pci_walk_bus(pdev->subordinate, pci_dev_d3cold_info, &d3cold_info);
+	pdev->no_d3cold = d3cold_info.no_d3cold;
+	pdev->d3cold_delay = d3cold_info.d3cold_delay;
+	return 0;
+}
+
+static int pcie_port_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+static int pci_dev_pme_poll(struct pci_dev *pdev, void *data)
+{
+	bool *pme_poll = data;
+
+	if (pdev->pme_poll)
+		*pme_poll = true;
+	return 0;
+}
+
+static int pcie_port_runtime_idle(struct device *dev)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	bool pme_poll = false;
+
+	/*
+	 * If any subordinate device needs pme poll, we should keep
+	 * the port in D0, because we need port in D0 to poll it.
+	 */
+	pci_walk_bus(pdev->subordinate, pci_dev_pme_poll, &pme_poll);
+	/* Delay for a short while to prevent too frequent suspend/resume */
+	if (!pme_poll)
+		pm_schedule_suspend(dev, 10);
+	return -EBUSY;
+}
+
 static const struct dev_pm_ops pcie_portdrv_pm_ops = {
 	.suspend	= pcie_port_device_suspend,
 	.resume		= pcie_port_device_resume,
@@ -101,6 +166,9 @@  static const struct dev_pm_ops pcie_portdrv_pm_ops = {
 	.poweroff	= pcie_port_device_suspend,
 	.restore	= pcie_port_device_resume,
 	.resume_noirq	= pcie_port_resume_noirq,
+	.runtime_suspend = pcie_port_runtime_suspend,
+	.runtime_resume = pcie_port_runtime_resume,
+	.runtime_idle	= pcie_port_runtime_idle,
 };
 
 #define PCIE_PORTDRV_PM_OPS	(&pcie_portdrv_pm_ops)