summaryrefslogtreecommitdiffstats
path: root/drivers/thunderbolt
diff options
context:
space:
mode:
authorMika Westerberg <mika.westerberg@linux.intel.com>2019-04-02 15:26:00 +0300
committerMika Westerberg <mika.westerberg@linux.intel.com>2020-09-03 12:06:42 +0300
commitb2be2b05cf3b1c7b499d3b05decdcc524879fea7 (patch)
tree039a570118a09344215a988952e313563a15772e /drivers/thunderbolt
parent1c9698f856699c7a36d8c53f146b64c4b915e5ad (diff)
downloadlinux-b2be2b05cf3b1c7b499d3b05decdcc524879fea7.tar.bz2
thunderbolt: Create device links from ACPI description
The new way to describe relationship between tunneled ports and USB4 NHI (Native Host Interface) is with ACPI _DSD looking like below for a PCIe downstream port: Scope (\_SB.PCI0) { Device (NHI0) { } // Thunderbolt NHI Device (DSB0) // Hotplug downstream port { Name (_DSD, Package () { ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), Package () { Package () {"usb4-host-interface", \_SB.PCI0.NHI0}, ... } }) } } This is "documented" in these [1] USB-IF slides and being used on systems that ship with Windows. The _DSD can be added to tunneled USB3 and PCIe ports, and is needed to make sure the USB4 NHI is resumed before any of the tunneled ports so the protocol tunnels get established properly before the actual port itself is resumed. Othwerwise the USB/PCI core find the link may not be established and starts tearing down the device stack. This parses the ACPI description each time NHI is probed and tries to find devices that has the property and it references the NHI in question. For each matching device a device link from that device to the NHI is created. Since USB3 ports themselves do not get runtime suspended with the parent device (hub) we do not add the link from the USB3 port to USB4 NHI but instead we add the link from the xHCI device. This makes the device link usable for runtime PM as well. [1] https://www.usb.org/sites/default/files/D1T2-2%20-%20USB4%20on%20Windows.pdf Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/thunderbolt')
-rw-r--r--drivers/thunderbolt/Makefile2
-rw-r--r--drivers/thunderbolt/acpi.c117
-rw-r--r--drivers/thunderbolt/nhi.c1
-rw-r--r--drivers/thunderbolt/tb.h6
4 files changed, 126 insertions, 0 deletions
diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index 4ab5bfad7bfd..754a529aa132 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -4,4 +4,6 @@ thunderbolt-objs := nhi.o nhi_ops.o ctl.o tb.o switch.o cap.o path.o tunnel.o ee
thunderbolt-objs += domain.o dma_port.o icm.o property.o xdomain.o lc.o tmu.o usb4.o
thunderbolt-objs += nvm.o retimer.o quirks.o
+thunderbolt-${CONFIG_ACPI} += acpi.o
+
obj-${CONFIG_USB4_KUNIT_TEST} += test.o
diff --git a/drivers/thunderbolt/acpi.c b/drivers/thunderbolt/acpi.c
new file mode 100644
index 000000000000..a5f988a9f948
--- /dev/null
+++ b/drivers/thunderbolt/acpi.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ACPI support
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/acpi.h>
+
+#include "tb.h"
+
+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 (nhi->pdev->dev.fwnode != 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_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;
+
+ link = device_link_add(&pdev->dev, &nhi->pdev->dev,
+ DL_FLAG_AUTOREMOVE_SUPPLIER |
+ 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));
+ }
+ }
+
+out_put:
+ fwnode_handle_put(args.fwnode);
+ return AE_OK;
+}
+
+/**
+ * tb_acpi_add_links() - Add device links based on ACPI description
+ * @nhi: Pointer to NHI
+ *
+ * Goes over ACPI namespace finding tunneled ports that reference to
+ * @nhi ACPI node. For each reference a device link is added. The link
+ * is automatically removed by the driver core.
+ */
+void tb_acpi_add_links(struct tb_nhi *nhi)
+{
+ acpi_status status;
+
+ if (!has_acpi_companion(&nhi->pdev->dev))
+ return;
+
+ /*
+ * Find all devices that have usb4-host-controller interface
+ * property that references to this NHI.
+ */
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 32,
+ tb_acpi_add_link, NULL, nhi, NULL);
+ if (ACPI_FAILURE(status))
+ dev_warn(&nhi->pdev->dev, "failed to enumerate tunneled ports\n");
+}
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index e499fe78756b..bd24e8254336 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -1199,6 +1199,7 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
}
tb_apple_add_links(nhi);
+ tb_acpi_add_links(nhi);
tb = icm_probe(nhi);
if (!tb)
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index e095ff5ead01..66eb766681f9 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -967,4 +967,10 @@ int usb4_usb3_port_release_bandwidth(struct tb_port *port, int *upstream_bw,
void tb_check_quirks(struct tb_switch *sw);
+#ifdef CONFIG_ACPI
+void tb_acpi_add_links(struct tb_nhi *nhi);
+#else
+static inline void tb_acpi_add_links(struct tb_nhi *nhi) { }
+#endif
+
#endif