drivers/thunderbolt/acpi.c

   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
  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  */
 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 }