Re: [PATCH 1/2] usb: core: add vendor hook for usb suspend and resume

From: Puma Hsu <pumahsu@google.com>
To: gregkh@linuxfoundation.org, mka@chromium.org, dianders@chromium.org
Cc: albertccwang@google.com, raychi@google.com, howardyen@google.com,
	leejj@google.com, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] usb: core: add vendor hook for usb suspend and resume
Date: Wed, 14 Dec 2022 15:20:01 +0800	[thread overview]
Message-ID: <CAGCq0LbRtpEZm2yseiAyTXApaArYvtx3q9KyJ6X+iiDGDpSMpQ@mail.gmail.com> (raw)
In-Reply-To: <20221214070650.703793-2-pumahsu@google.com>

On Wed, Dec 14, 2022 at 3:07 PM Puma Hsu <pumahsu@google.com> wrote:
>
> Add the hooks that vendor can design and bypass the suspend/resume.
> When the handled is set, skip the original suspend/resume process.
>
> In mobile, a co-processor can be used for USB audio. When the co-processor
> is working for USB audio, the co-processor is the user/owner of the USB
> driver, and the ACPU is able to sleep in such condition to improve power
> consumption. In original process, the ACPU will suspend/resume until the
> USB suspend/resume. We add the hooks, so we can control USB suspend/resume
> without affecting the ACPU.
>
> Signed-off-by: Puma Hsu <pumahsu@google.com>
> ---
>  drivers/usb/core/Makefile |  2 +-
>  drivers/usb/core/driver.c | 36 ++++++++++++++++++++++++++++++++++++
>  drivers/usb/core/usb.h    |  5 +++++
>  3 files changed, 42 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/Makefile b/drivers/usb/core/Makefile
> index 7d338e9c0657..f48f646cd874 100644
> --- a/drivers/usb/core/Makefile
> +++ b/drivers/usb/core/Makefile
> @@ -3,7 +3,7 @@
>  # Makefile for USB Core files and filesystem
>  #
>
> -usbcore-y := usb.o hub.o hcd.o urb.o message.o driver.o
> +usbcore-y := usb.o hub.o hcd.o urb.o message.o driver.o usb-hooks-impl-goog.o
>  usbcore-y += config.o file.o buffer.o sysfs.o endpoint.o
>  usbcore-y += devio.o notify.o generic.o quirks.o devices.o
>  usbcore-y += phy.o port.o

Sorry I should not add usb-hooks-impl-goog to the makefile.
I will upload a version2

> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
> index 7e7e119c253f..3d2cfb6c2277 100644
> --- a/drivers/usb/core/driver.c
> +++ b/drivers/usb/core/driver.c
> @@ -35,6 +35,25 @@
>  #include "usb.h"
>
>
> +static struct usb_device_vendor_ops *usb_dev_vendor_ops;
> +
> +int usb_dev_register_vendor_ops(struct usb_device_vendor_ops *vendor_ops)
> +{
> +       if (vendor_ops == NULL)
> +               return -EINVAL;
> +
> +       usb_dev_vendor_ops = vendor_ops;
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(usb_dev_register_vendor_ops);
> +
> +struct usb_device_vendor_ops *usb_vendor_get_ops(void)
> +{
> +       return usb_dev_vendor_ops;
> +}
> +EXPORT_SYMBOL_GPL(usb_vendor_get_ops);
> +
> +
>  /*
>   * Adds a new dynamic USBdevice ID to this driver,
>   * and cause the driver to probe for all devices again.
> @@ -1400,11 +1419,19 @@ static int usb_suspend_both(struct usb_device *udev, pm_message_t msg)
>         int                     status = 0;
>         int                     i = 0, n = 0;
>         struct usb_interface    *intf;
> +       bool                    handled;
> +       struct usb_device_vendor_ops *ops = usb_vendor_get_ops();
>
>         if (udev->state == USB_STATE_NOTATTACHED ||
>                         udev->state == USB_STATE_SUSPENDED)
>                 goto done;
>
> +       if (ops && ops->usb_dev_suspend) {
> +               handled = ops->usb_dev_suspend(udev, msg);
> +               if (handled)
> +                       goto done;
> +       }
> +
>         /* Suspend all the interfaces and then udev itself */
>         if (udev->actconfig) {
>                 n = udev->actconfig->desc.bNumInterfaces;
> @@ -1501,11 +1528,20 @@ static int usb_resume_both(struct usb_device *udev, pm_message_t msg)
>         int                     status = 0;
>         int                     i;
>         struct usb_interface    *intf;
> +       bool                    handled;
> +       struct usb_device_vendor_ops *ops = usb_vendor_get_ops();
>
>         if (udev->state == USB_STATE_NOTATTACHED) {
>                 status = -ENODEV;
>                 goto done;
>         }
> +
> +       if (ops && ops->usb_dev_resume) {
> +               handled = ops->usb_dev_resume(udev, msg);
> +               if (handled)
> +                       goto done;
> +       }
> +
>         udev->can_submit = 1;
>
>         /* Resume the device */
> diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
> index 82538daac8b8..9ccb8683071d 100644
> --- a/drivers/usb/core/usb.h
> +++ b/drivers/usb/core/usb.h
> @@ -220,3 +220,8 @@ extern acpi_handle usb_get_hub_port_acpi_handle(struct usb_device *hdev,
>  static inline int usb_acpi_register(void) { return 0; };
>  static inline void usb_acpi_unregister(void) { };
>  #endif
> +
> +struct usb_device_vendor_ops {
> +       bool (*usb_dev_suspend)(struct usb_device *udev, pm_message_t msg);
> +       bool (*usb_dev_resume)(struct usb_device *udev, pm_message_t msg);
> +};
> --
> 2.39.0.rc1.256.g54fd8350bd-goog
>