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![Rajmohan Mani](/assets/img/avatar_default.png)
Typically retimers can be accessed only when the USB4 link is up (e.g there is a cable connected). However, sometimes it is useful to be able to access retimers even if there is nothing connected to the USB4 port. For instance we may still want to be able to upgrade the retimer NVM firmware even if the user does not have any USB4 devices. This is something that USB4 spec leaves to implementers. In case of ACPI based systems, we can support this by providing a special _DSM method under each USB4 port. This _DSM can be used to turn on power to on-board retimers (and cycle it through different modes so that the sideband becomes usable). This patch adds support for this _DSM and makes the functionality available to the rest of the driver through tb_acpi_power_[on|off]_retimers(). Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com> Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
388 lines
10 KiB
C
388 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ACPI support
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*
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* Copyright (C) 2020, Intel Corporation
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* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
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*/
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#include <linux/acpi.h>
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#include "tb.h"
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static acpi_status tb_acpi_add_link(acpi_handle handle, u32 level, void *data,
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void **return_value)
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{
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struct fwnode_reference_args args;
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struct fwnode_handle *fwnode;
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struct tb_nhi *nhi = data;
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struct acpi_device *adev;
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struct pci_dev *pdev;
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struct device *dev;
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int ret;
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if (acpi_bus_get_device(handle, &adev))
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return AE_OK;
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fwnode = acpi_fwnode_handle(adev);
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ret = fwnode_property_get_reference_args(fwnode, "usb4-host-interface",
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NULL, 0, 0, &args);
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if (ret)
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return AE_OK;
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/* It needs to reference this NHI */
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if (nhi->pdev->dev.fwnode != args.fwnode)
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goto out_put;
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/*
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* Try to find physical device walking upwards to the hierarcy.
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* We need to do this because the xHCI driver might not yet be
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* bound so the USB3 SuperSpeed ports are not yet created.
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*/
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dev = acpi_get_first_physical_node(adev);
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while (!dev) {
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adev = adev->parent;
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if (!adev)
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break;
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dev = acpi_get_first_physical_node(adev);
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}
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if (!dev)
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goto out_put;
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/*
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* Check that the device is PCIe. This is because USB3
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* SuperSpeed ports have this property and they are not power
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* managed with the xHCI and the SuperSpeed hub so we create the
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* link from xHCI instead.
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*/
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while (dev && !dev_is_pci(dev))
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dev = dev->parent;
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if (!dev)
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goto out_put;
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/*
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* Check that this actually matches the type of device we
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* expect. It should either be xHCI or PCIe root/downstream
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* port.
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*/
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pdev = to_pci_dev(dev);
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if (pdev->class == PCI_CLASS_SERIAL_USB_XHCI ||
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(pci_is_pcie(pdev) &&
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(pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
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pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))) {
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const struct device_link *link;
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link = device_link_add(&pdev->dev, &nhi->pdev->dev,
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DL_FLAG_AUTOREMOVE_SUPPLIER |
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DL_FLAG_PM_RUNTIME);
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if (link) {
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dev_dbg(&nhi->pdev->dev, "created link from %s\n",
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dev_name(&pdev->dev));
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} else {
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dev_warn(&nhi->pdev->dev, "device link creation from %s failed\n",
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dev_name(&pdev->dev));
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}
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}
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out_put:
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fwnode_handle_put(args.fwnode);
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return AE_OK;
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}
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/**
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* tb_acpi_add_links() - Add device links based on ACPI description
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* @nhi: Pointer to NHI
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*
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* Goes over ACPI namespace finding tunneled ports that reference to
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* @nhi ACPI node. For each reference a device link is added. The link
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* is automatically removed by the driver core.
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*/
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void tb_acpi_add_links(struct tb_nhi *nhi)
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{
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acpi_status status;
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if (!has_acpi_companion(&nhi->pdev->dev))
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return;
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/*
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* Find all devices that have usb4-host-controller interface
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* property that references to this NHI.
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*/
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status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 32,
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tb_acpi_add_link, NULL, nhi, NULL);
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if (ACPI_FAILURE(status))
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dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
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}
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/**
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* tb_acpi_is_native() - Did the platform grant native TBT/USB4 control
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*
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* Returns %true if the platform granted OS native control over
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* TBT/USB4. In this case software based connection manager can be used,
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* otherwise there is firmware based connection manager running.
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*/
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bool tb_acpi_is_native(void)
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{
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return osc_sb_native_usb4_support_confirmed &&
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osc_sb_native_usb4_control;
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}
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/**
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* tb_acpi_may_tunnel_usb3() - Is USB3 tunneling allowed by the platform
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*
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* When software based connection manager is used, this function
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* returns %true if platform allows native USB3 tunneling.
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*/
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bool tb_acpi_may_tunnel_usb3(void)
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{
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if (tb_acpi_is_native())
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return osc_sb_native_usb4_control & OSC_USB_USB3_TUNNELING;
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return true;
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}
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/**
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* tb_acpi_may_tunnel_dp() - Is DisplayPort tunneling allowed by the platform
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*
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* When software based connection manager is used, this function
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* returns %true if platform allows native DP tunneling.
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*/
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bool tb_acpi_may_tunnel_dp(void)
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{
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if (tb_acpi_is_native())
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return osc_sb_native_usb4_control & OSC_USB_DP_TUNNELING;
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return true;
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}
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/**
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* tb_acpi_may_tunnel_pcie() - Is PCIe tunneling allowed by the platform
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*
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* When software based connection manager is used, this function
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* returns %true if platform allows native PCIe tunneling.
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*/
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bool tb_acpi_may_tunnel_pcie(void)
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{
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if (tb_acpi_is_native())
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return osc_sb_native_usb4_control & OSC_USB_PCIE_TUNNELING;
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return true;
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}
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/**
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* tb_acpi_is_xdomain_allowed() - Are XDomain connections allowed
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*
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* When software based connection manager is used, this function
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* returns %true if platform allows XDomain connections.
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*/
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bool tb_acpi_is_xdomain_allowed(void)
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{
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if (tb_acpi_is_native())
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return osc_sb_native_usb4_control & OSC_USB_XDOMAIN;
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return true;
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}
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/* UUID for retimer _DSM: e0053122-795b-4122-8a5e-57be1d26acb3 */
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static const guid_t retimer_dsm_guid =
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GUID_INIT(0xe0053122, 0x795b, 0x4122,
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0x8a, 0x5e, 0x57, 0xbe, 0x1d, 0x26, 0xac, 0xb3);
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#define RETIMER_DSM_QUERY_ONLINE_STATE 1
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#define RETIMER_DSM_SET_ONLINE_STATE 2
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static int tb_acpi_retimer_set_power(struct tb_port *port, bool power)
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{
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struct usb4_port *usb4 = port->usb4;
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union acpi_object argv4[2];
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struct acpi_device *adev;
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union acpi_object *obj;
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int ret;
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if (!usb4->can_offline)
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return 0;
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adev = ACPI_COMPANION(&usb4->dev);
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if (WARN_ON(!adev))
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return 0;
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/* Check if we are already powered on (and in correct mode) */
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obj = acpi_evaluate_dsm_typed(adev->handle, &retimer_dsm_guid, 1,
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RETIMER_DSM_QUERY_ONLINE_STATE, NULL,
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ACPI_TYPE_INTEGER);
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if (!obj) {
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tb_port_warn(port, "ACPI: query online _DSM failed\n");
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return -EIO;
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}
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ret = obj->integer.value;
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ACPI_FREE(obj);
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if (power == ret)
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return 0;
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tb_port_dbg(port, "ACPI: calling _DSM to power %s retimers\n",
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power ? "on" : "off");
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argv4[0].type = ACPI_TYPE_PACKAGE;
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argv4[0].package.count = 1;
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argv4[0].package.elements = &argv4[1];
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argv4[1].integer.type = ACPI_TYPE_INTEGER;
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argv4[1].integer.value = power;
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obj = acpi_evaluate_dsm_typed(adev->handle, &retimer_dsm_guid, 1,
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RETIMER_DSM_SET_ONLINE_STATE, argv4,
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ACPI_TYPE_INTEGER);
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if (!obj) {
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tb_port_warn(port,
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"ACPI: set online state _DSM evaluation failed\n");
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return -EIO;
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}
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ret = obj->integer.value;
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ACPI_FREE(obj);
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if (ret >= 0) {
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if (power)
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return ret == 1 ? 0 : -EBUSY;
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return 0;
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}
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tb_port_warn(port, "ACPI: set online state _DSM failed with error %d\n", ret);
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return -EIO;
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}
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/**
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* tb_acpi_power_on_retimers() - Call platform to power on retimers
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* @port: USB4 port
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*
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* Calls platform to turn on power to all retimers behind this USB4
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* port. After this function returns successfully the caller can
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* continue with the normal retimer flows (as specified in the USB4
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* spec). Note if this returns %-EBUSY it means the type-C port is in
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* non-USB4/TBT mode (there is non-USB4/TBT device connected).
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*
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* This should only be called if the USB4/TBT link is not up.
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*
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* Returns %0 on success.
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*/
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int tb_acpi_power_on_retimers(struct tb_port *port)
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{
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return tb_acpi_retimer_set_power(port, true);
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}
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/**
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* tb_acpi_power_off_retimers() - Call platform to power off retimers
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* @port: USB4 port
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*
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* This is the opposite of tb_acpi_power_on_retimers(). After returning
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* successfully the normal operations with the @port can continue.
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*
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* Returns %0 on success.
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*/
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int tb_acpi_power_off_retimers(struct tb_port *port)
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{
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return tb_acpi_retimer_set_power(port, false);
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}
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static bool tb_acpi_bus_match(struct device *dev)
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{
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return tb_is_switch(dev) || tb_is_usb4_port_device(dev);
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}
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static struct acpi_device *tb_acpi_find_port(struct acpi_device *adev,
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const struct tb_port *port)
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{
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struct acpi_device *port_adev;
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if (!adev)
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return NULL;
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/*
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* Device routers exists under the downstream facing USB4 port
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* of the parent router. Their _ADR is always 0.
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*/
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list_for_each_entry(port_adev, &adev->children, node) {
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if (acpi_device_adr(port_adev) == port->port)
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return port_adev;
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}
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return NULL;
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}
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static struct acpi_device *tb_acpi_switch_find_companion(struct tb_switch *sw)
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{
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struct acpi_device *adev = NULL;
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struct tb_switch *parent_sw;
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parent_sw = tb_switch_parent(sw);
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if (parent_sw) {
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struct tb_port *port = tb_port_at(tb_route(sw), parent_sw);
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struct acpi_device *port_adev;
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port_adev = tb_acpi_find_port(ACPI_COMPANION(&parent_sw->dev), port);
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if (port_adev)
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adev = acpi_find_child_device(port_adev, 0, false);
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} else {
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struct tb_nhi *nhi = sw->tb->nhi;
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struct acpi_device *parent_adev;
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parent_adev = ACPI_COMPANION(&nhi->pdev->dev);
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if (parent_adev)
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adev = acpi_find_child_device(parent_adev, 0, false);
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}
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return adev;
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}
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static struct acpi_device *tb_acpi_find_companion(struct device *dev)
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{
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/*
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* The Thunderbolt/USB4 hierarchy looks like following:
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*
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* Device (NHI)
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* Device (HR) // Host router _ADR == 0
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* Device (DFP0) // Downstream port _ADR == lane 0 adapter
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* Device (DR) // Device router _ADR == 0
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* Device (UFP) // Upstream port _ADR == lane 0 adapter
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* Device (DFP1) // Downstream port _ADR == lane 0 adapter number
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*
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* At the moment we bind the host router to the corresponding
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* Linux device.
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*/
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if (tb_is_switch(dev))
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return tb_acpi_switch_find_companion(tb_to_switch(dev));
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else if (tb_is_usb4_port_device(dev))
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return tb_acpi_find_port(ACPI_COMPANION(dev->parent),
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tb_to_usb4_port_device(dev)->port);
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return NULL;
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}
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static void tb_acpi_setup(struct device *dev)
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{
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struct acpi_device *adev = ACPI_COMPANION(dev);
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struct usb4_port *usb4 = tb_to_usb4_port_device(dev);
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if (!adev || !usb4)
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return;
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if (acpi_check_dsm(adev->handle, &retimer_dsm_guid, 1,
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BIT(RETIMER_DSM_QUERY_ONLINE_STATE) |
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BIT(RETIMER_DSM_SET_ONLINE_STATE)))
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usb4->can_offline = true;
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}
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static struct acpi_bus_type tb_acpi_bus = {
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.name = "thunderbolt",
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.match = tb_acpi_bus_match,
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.find_companion = tb_acpi_find_companion,
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.setup = tb_acpi_setup,
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};
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int tb_acpi_init(void)
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{
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return register_acpi_bus_type(&tb_acpi_bus);
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}
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void tb_acpi_exit(void)
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{
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unregister_acpi_bus_type(&tb_acpi_bus);
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}
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