From nobody Fri Sep 12 04:48:25 2025 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C60833A028 for ; Thu, 11 Sep 2025 14:21:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757600477; cv=none; b=TwOyWYqolB/5a+9Hsw+eK82EuwvseaM3xQcf4/GOZPJm3At2GIz0/XlWx6yIKbeyI1cCS0kWHGlO+Lf7zZlSKFb9Ok2OQrz0dF9LtqSoSWpWpd7HwMGsWo1+fvZdTRrK0pUgi9nNdZg0dM4PRaXsqXZEYYj02xLRrd4blWrjx3U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757600477; c=relaxed/simple; bh=ZBEWXSIeqmrC3ds4q0dvNNt4iprgbUvOMgGvcwRwVCM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Ls0iOu6Em9mYXRnYbyNoBj/pgXNzUQeag7ThW5DwnevGD6Qh2LcW1fxIJYkQZKUHiKe8MOBWpb842XYtlO36elkl6nSN/U1M6fHgvlwO4YFNGckQEw+Qk30G+X9zyuirOUx1VcWYk35lvq4nIvwEC1CIqoPfZ1VI2Yyjf1HzJ1s= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--guanyulin.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=sC8xv1PT; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--guanyulin.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sC8xv1PT" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b4fbb90b453so987515a12.2 for ; Thu, 11 Sep 2025 07:21:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1757600474; x=1758205274; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=cd4UolCkEdo/ZISJT1rflmMGOeP6XETs53xAhFcvlpo=; b=sC8xv1PT3luryLK1V70Fx2Y1wtK8KFDeeU83ulh35vEhPmgTpqUIvufamoqVCGCDuZ LFP2l6v8vF7U2ZHmiygpKIq4kT5AI9W8MJ249nLMIRC2T5iTw9LZfRwNNDQLaTuHr0Kp KJHgsNwnttozhhUXrx7qS6/FMM838bZ2FuS03FptfU40UPzWyxMzuStPFqwE94zkS9/4 +F7NhT43MJFbhHPkuwybJBrJfPUALzaY8jhEa0tE53pOo5w4kNq1deyK3EysLlrbYYeC AKLplgsA2Jqw6FZryCSKL0xK5ijjDYKwG4DQ40VyFh9jm9C6k8ZIllw/Y54lji2XXj9/ /bcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757600474; x=1758205274; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=cd4UolCkEdo/ZISJT1rflmMGOeP6XETs53xAhFcvlpo=; b=pxbpIj+Ar+OrAHJmVApVGae6iayfHxApolrMQHuAmYaH5q5N+B36MFZBk+nPNqRU/0 s1kiPfaUNlKGcCz+2Pu4Z9aO6RCe4JrJqLW4t1WRucQQoo16ijUYBN7+Go1aiblBUt3C Zv9zGaSSjbEHSrVpuitR8RTBmc4JG8Y7DTTzcHocNzgUUWrHlJzZzXjifh2RtIeICFyW O+bD/y7ZVFSzXgiQgs9XR1fpL3kQY3eY3P/lxyW7XIHV4KCjf4uT5mQuj0YYq9xt5WV8 Q774Os58/j/33Oi08+W5VEZpdI/773prmvBMr+41GUbdpzDdikGjMelXbkBNwRJKlXe8 RDYQ== X-Forwarded-Encrypted: i=1; AJvYcCVtVnWL4NgxO0Hql5jZupUTPqaEEi6BKZ7FgChu8d7oU2PPXt9dVP4ZC7ldA7lGLuUMEVLh60bLXf8EYFk=@vger.kernel.org X-Gm-Message-State: AOJu0YyVSc5u+tD7BqVlEE+m3ITfqvW017TAZE5T6NzVTM4R+Z2ig51r HllAIcPaS6xYYpWKxINIxUk2QSzt639CRBrKWztXCHmUeKkiargr2KltXporWY2X0vqO9+yRhW5 olji9WP+d0KJ9YeOhfQ== X-Google-Smtp-Source: AGHT+IHIv06rwyIboIBXdOUfS11nPVbWxBONJJC6nZ8x4coRAIHSyEYiKps3YULVIH9Uh7RGK9BYFphhlPjrOQU= X-Received: from pgac28.prod.google.com ([2002:a05:6a02:295c:b0:b49:dbc4:f7a8]) (user=guanyulin job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:a10a:b0:251:e4b4:7a44 with SMTP id adf61e73a8af0-2534556ea5emr29031640637.41.1757600474392; Thu, 11 Sep 2025 07:21:14 -0700 (PDT) Date: Thu, 11 Sep 2025 14:20:14 +0000 In-Reply-To: <20250911142051.90822-1-guanyulin@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250911142051.90822-1-guanyulin@google.com> X-Mailer: git-send-email 2.51.0.384.g4c02a37b29-goog Message-ID: <20250911142051.90822-3-guanyulin@google.com> Subject: [PATCH v16 2/4] usb: offload: add apis for offload usage tracking From: Guan-Yu Lin To: gregkh@linuxfoundation.org, mathias.nyman@intel.com, hannelotta@gmail.com, zijun.hu@oss.qualcomm.com, xu.yang_2@nxp.com, stern@rowland.harvard.edu, andriy.shevchenko@linux.intel.com, amardeep.rai@intel.com, dominique.martinet@atmark-techno.com, quic_wcheng@quicinc.com, sakari.ailus@linux.intel.com, dh10.jung@samsung.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Guan-Yu Lin Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Introduce offload_usage and corresponding apis to track offload usage on each USB device. Offload denotes that there is another co-processor accessing the USB device via the same USB host controller. To optimize power usage, it's essential to monitor whether the USB device is actively used by other co-processor. This information is vital when determining if a USB device can be safely suspended during system power state transitions. Signed-off-by: Guan-Yu Lin --- drivers/usb/core/Makefile | 1 + drivers/usb/core/offload.c | 136 +++++++++++++++++++++++++++++++++++++ drivers/usb/core/usb.c | 1 + include/linux/usb.h | 18 +++++ 4 files changed, 156 insertions(+) create mode 100644 drivers/usb/core/offload.c diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile index ac006abd13b3..766000b4939e 100644 --- a/drivers/usb/core/Makefile +++ b/drivers/usb/core/Makefile @@ -9,6 +9,7 @@ usbcore-y +=3D devio.o notify.o generic.o quirks.o devices.o usbcore-y +=3D phy.o port.o =20 usbcore-$(CONFIG_OF) +=3D of.o +usbcore-$(CONFIG_USB_XHCI_SIDEBAND) +=3D offload.o usbcore-$(CONFIG_USB_PCI) +=3D hcd-pci.o usbcore-$(CONFIG_ACPI) +=3D usb-acpi.o =20 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 + +#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 handlin= g 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 =3D=3D USB_STATE_NOTATTACHED) { + usb_unlock_device(udev); + return -ENODEV; + } + + if (udev->state =3D=3D 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 =3D 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 =3D=3D USB_STATE_NOTATTACHED) { + usb_unlock_device(udev); + return -ENODEV; + } + + if (udev->state =3D=3D 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 =3D 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. Th= is + * information could be used for power management or other forms of resour= ce + * 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->mu= tex) +{ + struct usb_device *child; + bool active; + int port1; + + usb_hub_for_each_child(udev, port1, child) { + usb_lock_device(child); + active =3D usb_offload_check(child); + usb_unlock_device(child); + if (active) + return true; + } + + return !!udev->offload_usage; +} +EXPORT_SYMBOL_GPL(usb_offload_check); diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c index b88b6271cb30..b6b0b8489523 100644 --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -670,6 +670,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *par= ent, set_dev_node(&dev->dev, dev_to_node(bus->sysdev)); dev->state =3D USB_STATE_ATTACHED; dev->lpm_disable_count =3D 1; + dev->offload_usage =3D 0; atomic_set(&dev->urbnum, 0); =20 INIT_LIST_HEAD(&dev->ep0.urb_list); diff --git a/include/linux/usb.h b/include/linux/usb.h index 70ef00c42d22..e85105939af8 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -636,6 +636,8 @@ struct usb3_lpm_parameters { * @do_remote_wakeup: remote wakeup should be enabled * @reset_resume: needs reset instead of resume * @port_is_suspended: the upstream port is suspended (L2 or U3) + * @offload_at_suspend: offload activities during suspend is enabled. + * @offload_usage: number of offload activities happening on this usb devi= ce. * @slot_id: Slot ID assigned by xHCI * @l1_params: best effor service latency for USB2 L1 LPM state, and L1 ti= meout. * @u1_params: exit latencies for USB3 U1 LPM state, and hub-initiated tim= eout. @@ -724,6 +726,8 @@ struct usb_device { unsigned do_remote_wakeup:1; unsigned reset_resume:1; unsigned port_is_suspended:1; + unsigned offload_at_suspend:1; + int offload_usage; enum usb_link_tunnel_mode tunnel_mode; struct device_link *usb4_link; =20 @@ -841,6 +845,20 @@ static inline void usb_mark_last_busy(struct usb_devic= e *udev) { } #endif =20 +#if IS_ENABLED(CONFIG_USB_XHCI_SIDEBAND) +int usb_offload_get(struct usb_device *udev); +int usb_offload_put(struct usb_device *udev); +bool usb_offload_check(struct usb_device *udev); +#else + +static inline int usb_offload_get(struct usb_device *udev) +{ return 0; } +static inline int usb_offload_put(struct usb_device *udev) +{ return 0; } +static inline bool usb_offload_check(struct usb_device *udev) +{ return false; } +#endif + extern int usb_disable_lpm(struct usb_device *udev); extern void usb_enable_lpm(struct usb_device *udev); /* Same as above, but these functions lock/unlock the bandwidth_mutex. */ --=20 2.51.0.384.g4c02a37b29-goog