1// SPDX-License-Identifier: GPL-2.0
2/*
3 * ACPI support
4 *
5 * Copyright (C) 2020, Intel Corporation
6 * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
7 */
8
9#include <linux/acpi.h>
10#include <linux/pm_runtime.h>
11
12#include "tb.h"
13
14static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
15				    void **return_value)
16{
17	struct fwnode_reference_args args;
18	struct fwnode_handle *fwnode;
19	struct tb_nhi *nhi = data;
20	struct acpi_device *adev;
21	struct pci_dev *pdev;
22	struct device *dev;
23	int ret;
24
25	if (acpi_bus_get_device(handle, &adev))
26		return AE_OK;
27
28	fwnode = acpi_fwnode_handle(adev);
29	ret = fwnode_property_get_reference_args(fwnode, "usb4-host-interface",
30						 NULL, 0, 0, &args);
31	if (ret)
32		return AE_OK;
33
34	/* It needs to reference this NHI */
35	if (nhi->pdev->dev.fwnode != args.fwnode)
36		goto out_put;
37
38	/*
39	 * Try to find physical device walking upwards to the hierarcy.
40	 * We need to do this because the xHCI driver might not yet be
41	 * bound so the USB3 SuperSpeed ports are not yet created.
42	 */
43	dev = acpi_get_first_physical_node(adev);
44	while (!dev) {
45		adev = adev->parent;
46		if (!adev)
47			break;
48		dev = acpi_get_first_physical_node(adev);
49	}
50
51	if (!dev)
52		goto out_put;
53
54	/*
55	 * Check that the device is PCIe. This is because USB3
56	 * SuperSpeed ports have this property and they are not power
57	 * managed with the xHCI and the SuperSpeed hub so we create the
58	 * link from xHCI instead.
59	 */
60	while (dev && !dev_is_pci(dev))
61		dev = dev->parent;
62
63	if (!dev)
64		goto out_put;
65
66	/*
67	 * Check that this actually matches the type of device we
68	 * expect. It should either be xHCI or PCIe root/downstream
69	 * port.
70	 */
71	pdev = to_pci_dev(dev);
72	if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI ||
73	    (pci_is_pcie(pdev) &&
74		(pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
75		 pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) {
76		const struct device_link *link;
77
78		/*
79		 * Make them both active first to make sure the NHI does
80		 * not runtime suspend before the consumer. The
81		 * pm_runtime_put() below then allows the consumer to
82		 * runtime suspend again (which then allows NHI runtime
83		 * suspend too now that the device link is established).
84		 */
85		pm_runtime_get_sync(&pdev->dev);
86
87		link = device_link_add(&pdev->dev, &nhi->pdev->dev,
88				       DL_FLAG_AUTOREMOVE_SUPPLIER |
89				       DL_FLAG_RPM_ACTIVE |
90				       DL_FLAG_PM_RUNTIME);
91		if (link) {
92			dev_dbg(&nhi->pdev->dev, "created link from %s\n",
93				dev_name(&pdev->dev));
94		} else {
95			dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n",
96				 dev_name(&pdev->dev));
97		}
98
99		pm_runtime_put(&pdev->dev);
100	}
101
102out_put:
103	fwnode_handle_put(args.fwnode);
104	return AE_OK;
105}
106
107/**
108 * tb_acpi_add_links() - Add device links based on ACPI description
109 * @nhi: Pointer to NHI
110 *
111 * Goes over ACPI namespace finding tunneled ports that reference to
112 * @nhi ACPI node. For each reference a device link is added. The link
113 * is automatically removed by the driver core.
114 */
115void tb_acpi_add_links(struct tb_nhi *nhi)
116{
117	acpi_status status;
118
119	if (!has_acpi_companion(&nhi->pdev->dev))
120		return;
121
122	/*
123	 * Find all devices that have usb4-host-controller interface
124	 * property that references to this NHI.
125	 */
126	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 32,
127				     tb_acpi_add_link, NULL, nhi, NULL);
128	if (ACPI_FAILURE(status))
129		dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
130}
131