[PATCH 0/8] virtio-usb: add dual-role virtio USB driver

[Igor Skalkin <igor.skalkin@oss.qualcomm.com>]

This series adds a new virtio-usb driver: a dual-role virtio device
capable of acting as a USB host controller, a USB device controller,
or both simultaneously with runtime role switching between the two
(USB OTG-style role switching) on ports that support it.

The corresponding virtio-usb device specification has been posted to
virtio-comment for review. This series matches the v2 revision of
that spec, which reconciles a small number of protocol details
(per-role virtqueue presentation, host-role vp_idx for hub/multi-VP
support, and the device-role BIND/UNBIND event split) that were
clarified while integrating and testing this driver against the
spec:

  [RFC PATCH v2] virtio-usb: Add initial virtio-usb specification
  Igor Skalkin <igor.skalkin@oss.qualcomm.com>
  virtio-comment@lists.linux.dev
  https://lore.kernel.org/virtio-comment/20260924154007.143927-1-igor.skalkin@oss.qualcomm.com/

This driver has been tested end-to-end against our own userspace
virtio-usb device implementation (host-side backend) in two setups:
  - arm64 hardware with a type-1 hypervisor, exercising a real dwc3
    USB controller on the host side.
  - x86 with a type-2 hypervisor (QEMU/KVM), using dummy_hcd/dummy_udc
    on the host side in place of real USB hardware.
Host role and device role were exercised in both setups: testusb on
the guest, over a virtualized host port, against g_zero running on
a real hardware UDC or on dummy UDC on the host side (host role);
and testusb on the host side, against g_zero running on a virtualized
UDC on the guest (device role); plus real USB mass-storage
hardware/gadgets and iperf3 over usbnet. Role switching was exercised
in both setups as well, but not with a real OTG cable/ID-pin connection:
on dwc3, role switching was driven through its "role-switch" sysfs
configuration; on dummy_hcd, it was emulated by toggling between two
simultaneously-configured dummy_hcd instances on the same port.
Testing with a real OTG connection is planned as a follow-up.

Known scope: this driver virtualizes an entire UDC per device-role
port, with each port owned by a single guest. USB function-level
virtualization - a single physical UDC exposing a composite gadget
whose individual functions are routed to different guests - is a
separate approach currently being explored, and is out of scope for
this series.

Patch summary:
  1:   protocol header and skeleton dual-role driver (probe/remove
       plumbing, no role support yet).
  2:   USB host controller (HCD) role support.
  3:   USB device controller (UDC) role support.
  4-5: USB OTG-style role query and role-switching support.
  6:   endpoint-lifecycle robustness rework (async split-phase state
       machine, replacing an earlier out-of-tree gadget.nonatomic
       patch that didn't pass upstream review).
  7:   SuperSpeed device-role support.
  8:   guest UDC naming fix (name prefix from the bind event).

Aiswarya Cyriac (3):
  virtio-usb: add protocol header and skeleton dual-role driver
  virtio-usb: add host role (USB Host Controller) support
  virtio-usb: add device role (USB Device Controller) support

Igor Skalkin (5):
  virtio-usb: add OTG role query support
  virtio-usb: add USB On-The-Go role-switching support
  virtio-usb: rework endpoint lifecycle to an async split-phase state
    machine
  virtio-usb: add SuperSpeed device-role support
  virtio-usb: support a guest UDC name prefix from the bind event

 MAINTAINERS                         |   10 +
 drivers/usb/Kconfig                 |    2 +
 drivers/usb/Makefile                |    1 +
 drivers/usb/virtio_usb/Kconfig      |   21 +
 drivers/usb/virtio_usb/Makefile     |    9 +
 drivers/usb/virtio_usb/controller.c |  422 ++++++++
 drivers/usb/virtio_usb/controller.h |  152 +++
 drivers/usb/virtio_usb/device.c     | 1893 +++++++++++++++++++++++++++++++++++
 drivers/usb/virtio_usb/device.h     |  115 +++
 drivers/usb/virtio_usb/host.c       | 1368 +++++++++++++++++++++++++
 drivers/usb/virtio_usb/host.h       |  203 ++++
 drivers/usb/virtio_usb/otg.c        |  403 ++++++++
 drivers/usb/virtio_usb/otg.h        |   38 +
 drivers/usb/virtio_usb/vq_common.c  |  740 ++++++++++++++
 drivers/usb/virtio_usb/vq_common.h  |  163 +++
 include/uapi/linux/virtio_usb.h     |  346 +++++++
 16 files changed, 5886 insertions(+)
 create mode 100644 drivers/usb/virtio_usb/Kconfig
 create mode 100644 drivers/usb/virtio_usb/Makefile
 create mode 100644 drivers/usb/virtio_usb/controller.c
 create mode 100644 drivers/usb/virtio_usb/controller.h
 create mode 100644 drivers/usb/virtio_usb/device.c
 create mode 100644 drivers/usb/virtio_usb/device.h
 create mode 100644 drivers/usb/virtio_usb/host.c
 create mode 100644 drivers/usb/virtio_usb/host.h
 create mode 100644 drivers/usb/virtio_usb/otg.c
 create mode 100644 drivers/usb/virtio_usb/otg.h
 create mode 100644 drivers/usb/virtio_usb/vq_common.c
 create mode 100644 drivers/usb/virtio_usb/vq_common.h
 create mode 100644 include/uapi/linux/virtio_usb.h

-- 
2.49.0