Merge tag 'usb-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB / Thunderbolt updates from Greg KH:
 "Here is the big set of USB and thunderbolt drivers for 6.18-rc1. It
  was another normal development cycle, with lots of the usual drivers
  getting updates:

   - Thunderbolt driver cleanups and additions

   - dwc3 driver updates

   - dwc2 driver updates

   - typec driver updates

   - xhci driver updates and additions

   - offload USB engine updates for better power management

   - unused tracepoint removals

   - usb gadget fixes and updates as more users start to rely on these
     drivers instead of the "old" function gadget drivers

   - new USB device ids

   - other minor driver USB driver updates

   - new USB I/O driver framework and driver additions"

  The last item, the usb i/o driver, has an i2c and gpio driver added
  through this tree. Those drivers were acked by the respective
  subsystem maintainers.

  All of these have been in linux-next for a while"

* tag 'usb-6.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (132 commits)
  usb: vhci-hcd: Prevent suspending virtually attached devices
  USB: serial: option: add SIMCom 8230C compositions
  thunderbolt: Fix use-after-free in tb_dp_dprx_work
  usb: xhci: align PORTSC trace with one-based port numbering
  usb: xhci: correct indentation for PORTSC tracing function
  usb: xhci: improve TR Dequeue Pointer mask
  usb: xhci-pci: add support for hosts with zero USB3 ports
  usb: xhci: Update a comment about Stop Endpoint retries
  Revert "usb: xhci: Avoid Stop Endpoint retry loop if the endpoint seems Running"
  usb: gadget: f_rndis: Refactor bind path to use __free()
  usb: gadget: f_ecm: Refactor bind path to use __free()
  usb: gadget: f_acm: Refactor bind path to use __free()
  usb: gadget: f_ncm: Refactor bind path to use __free()
  usb: gadget: Introduce free_usb_request helper
  usb: gadget: Store endpoint pointer in usb_request
  usb: host: xhci-rcar: Add Renesas RZ/G3E USB3 Host driver support
  usb: host: xhci-plat: Add .post_resume_quirk for struct xhci_plat_priv
  usb: host: xhci-rcar: Move R-Car reg definitions
  dt-bindings: usb: Document Renesas RZ/G3E USB3HOST
  usb: gadget: f_fs: Fix epfile null pointer access after ep enable.
  ...

1 files changed, 136 insertions, 0 deletions

diff --git a/drivers/usb/core/offload.c b/drivers/usb/core/offload.c
new file mode 100644
index 000000000000..7c699f1b8d2b
--- /dev/null
+++ b/drivers/usb/core/offload.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * offload.c - USB offload related functions
+ *
+ * Copyright (c) 2025, Google LLC.
+ *
+ * Author: Guan-Yu Lin
+ */
+
+#include <linux/usb.h>
+
+#include "usb.h"
+
+/**
+ * usb_offload_get - increment the offload_usage of a USB device
+ * @udev: the USB device to increment its offload_usage
+ *
+ * Incrementing the offload_usage of a usb_device indicates that offload is
+ * enabled on this usb_device; that is, another entity is actively handling USB
+ * transfers. This information allows the USB driver to adjust its power
+ * management policy based on offload activity.
+ *
+ * Return: 0 on success. A negative error code otherwise.
+ */
+int usb_offload_get(struct usb_device *udev)
+{
+	int ret;
+
+	usb_lock_device(udev);
+	if (udev->state == USB_STATE_NOTATTACHED) {
+		usb_unlock_device(udev);
+		return -ENODEV;
+	}
+
+	if (udev->state == USB_STATE_SUSPENDED ||
+		   udev->offload_at_suspend) {
+		usb_unlock_device(udev);
+		return -EBUSY;
+	}
+
+	/*
+	 * offload_usage could only be modified when the device is active, since
+	 * it will alter the suspend flow of the device.
+	 */
+	ret = usb_autoresume_device(udev);
+	if (ret < 0) {
+		usb_unlock_device(udev);
+		return ret;
+	}
+
+	udev->offload_usage++;
+	usb_autosuspend_device(udev);
+	usb_unlock_device(udev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_offload_get);
+
+/**
+ * usb_offload_put - drop the offload_usage of a USB device
+ * @udev: the USB device to drop its offload_usage
+ *
+ * The inverse operation of usb_offload_get, which drops the offload_usage of
+ * a USB device. This information allows the USB driver to adjust its power
+ * management policy based on offload activity.
+ *
+ * Return: 0 on success. A negative error code otherwise.
+ */
+int usb_offload_put(struct usb_device *udev)
+{
+	int ret;
+
+	usb_lock_device(udev);
+	if (udev->state == USB_STATE_NOTATTACHED) {
+		usb_unlock_device(udev);
+		return -ENODEV;
+	}
+
+	if (udev->state == USB_STATE_SUSPENDED ||
+		   udev->offload_at_suspend) {
+		usb_unlock_device(udev);
+		return -EBUSY;
+	}
+
+	/*
+	 * offload_usage could only be modified when the device is active, since
+	 * it will alter the suspend flow of the device.
+	 */
+	ret = usb_autoresume_device(udev);
+	if (ret < 0) {
+		usb_unlock_device(udev);
+		return ret;
+	}
+
+	/* Drop the count when it wasn't 0, ignore the operation otherwise. */
+	if (udev->offload_usage)
+		udev->offload_usage--;
+	usb_autosuspend_device(udev);
+	usb_unlock_device(udev);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(usb_offload_put);
+
+/**
+ * usb_offload_check - check offload activities on a USB device
+ * @udev: the USB device to check its offload activity.
+ *
+ * Check if there are any offload activity on the USB device right now. This
+ * information could be used for power management or other forms of resource
+ * management.
+ *
+ * The caller must hold @udev's device lock. In addition, the caller should
+ * ensure downstream usb devices are all either suspended or marked as
+ * "offload_at_suspend" to ensure the correctness of the return value.
+ *
+ * Returns true on any offload activity, false otherwise.
+ */
+bool usb_offload_check(struct usb_device *udev) __must_hold(&udev->dev->mutex)
+{
+	struct usb_device *child;
+	bool active;
+	int port1;
+
+	usb_hub_for_each_child(udev, port1, child) {
+		usb_lock_device(child);
+		active = usb_offload_check(child);
+		usb_unlock_device(child);
+		if (active)
+			return true;
+	}
+
+	return !!udev->offload_usage;
+}
+EXPORT_SYMBOL_GPL(usb_offload_check);