static acpi_status tb_acpi_add_link()

in acpi.c [14:105]

• 56 lines of code
• 15 McCabe index (conditional complexity)

static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
				    void **return_value)
{
	struct fwnode_reference_args args;
	struct fwnode_handle *fwnode;
	struct tb_nhi *nhi = data;
	struct acpi_device *adev;
	struct pci_dev *pdev;
	struct device *dev;
	int ret;

	if (acpi_bus_get_device(handle, &adev))
		return AE_OK;

	fwnode = acpi_fwnode_handle(adev);
	ret = fwnode_property_get_reference_args(fwnode, "usb4-host-interface",
						 NULL, 0, 0, &args);
	if (ret)
		return AE_OK;

	/* It needs to reference this NHI */
	if (dev_fwnode(&nhi->pdev->dev) != args.fwnode)
		goto out_put;

	/*
	 * Try to find physical device walking upwards to the hierarcy.
	 * We need to do this because the xHCI driver might not yet be
	 * bound so the USB3 SuperSpeed ports are not yet created.
	 */
	dev = acpi_get_first_physical_node(adev);
	while (!dev) {
		adev = adev->parent;
		if (!adev)
			break;
		dev = acpi_get_first_physical_node(adev);
	}

	if (!dev)
		goto out_put;

	/*
	 * Check that the device is PCIe. This is because USB3
	 * SuperSpeed ports have this property and they are not power
	 * managed with the xHCI and the SuperSpeed hub so we create the
	 * link from xHCI instead.
	 */
	while (dev && !dev_is_pci(dev))
		dev = dev->parent;

	if (!dev)
		goto out_put;

	/*
	 * Check that this actually matches the type of device we
	 * expect. It should either be xHCI or PCIe root/downstream
	 * port.
	 */
	pdev = to_pci_dev(dev);
	if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI ||
	    (pci_is_pcie(pdev) &&
		(pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
		 pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) {
		const struct device_link *link;

		/*
		 * Make them both active first to make sure the NHI does
		 * not runtime suspend before the consumer. The
		 * pm_runtime_put() below then allows the consumer to
		 * runtime suspend again (which then allows NHI runtime
		 * suspend too now that the device link is established).
		 */
		pm_runtime_get_sync(&pdev->dev);

		link = device_link_add(&pdev->dev, &nhi->pdev->dev,
				       DL_FLAG_AUTOREMOVE_SUPPLIER |
				       DL_FLAG_RPM_ACTIVE |
				       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));
		}

		pm_runtime_put(&pdev->dev);
	}

out_put:
	fwnode_handle_put(args.fwnode);
	return AE_OK;
}