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