Enum UsbFunctionInterfaceRequest 

pub enum UsbFunctionInterfaceRequest {
    Control {
        setup: UsbSetup,
        write: Vec<u8>,
        responder: UsbFunctionInterfaceControlResponder,
    },
    SetConfigured {
        configured: bool,
        speed: UsbSpeed,
        responder: UsbFunctionInterfaceSetConfiguredResponder,
    },
    SetInterface {
        interface: u8,
        alt_setting: u8,
        responder: UsbFunctionInterfaceSetInterfaceResponder,
    },
    #[non_exhaustive]
    _UnknownMethod {
        ordinal: u64,
        control_handle: UsbFunctionInterfaceControlHandle,
        method_type: MethodType,
    },
}

Protocol offered to [UsbFunction] instances to handle host-initiated requests.

This protocol is implemented by the USB function driver (protocol server) and called by the USB peripheral controller (protocol client).

Variants

Control

Callback for handling EP0 class/vendor-specific control requests targeting the interface(s) owned by this function.

This is called when the host sends a control request to the device. The protocol server (of [UsbFunctionInterface]) should process the request and return the result.

The host expects a response within a strict timeout period defined by the USB specification Section 9.2.6 (50ms for requests without data, and 500ms for read data stages). Because of these hardware-enforced limits, the implementation must reply as quickly as possible and avoid blocking the dispatcher.

setup is the control request metadata (setup packet). write contains the raw bytes sent by the host in the Data Stage of a host-to-device (OUT) control transfer. It is empty for device-to-host (IN) transfers. read in the response payload contains the raw bytes returned to the host in the Data Stage of a device-to-host (IN) control transfer. It must be empty for host-to-device (OUT) transfers.

Any error returned by this method (including ZX_ERR_NOT_SUPPORTED) causes the peripheral controller to stall Endpoint 0, signaling a “Request Error” to the host.

• error:
  • ZX_ERR_NOT_SUPPORTED if the request is not supported by the protocol server.
  • ZX_ERR_INVALID_ARGS if the setup packet or data is invalid.
  • ZX_ERR_IO_NOT_PRESENT if the device was disconnected while processing the request.

Fields

setup: UsbSetup

write: Vec<u8>

responder: UsbFunctionInterfaceControlResponder

SetConfigured

Inform the protocol server (of [UsbFunctionInterface]) when the USB device configured state changes.

Called with configured == true in response to a SET_CONFIGURATION control request that selects a configuration that contains this function. In this case, the protocol server should use [UsbFunction.ConfigureEndpoint] to configure its endpoints.

Per USB 2.0 Specification Section 9.4.7, receiving a SET_CONFIGURATION request when the function is already configured is valid and should reset/re-initialize the function state rather than returning an error.

Called with configured == false when configuration is disabled or USB is disconnected. The protocol server should then use [UsbFunction.DisableEndpoint] to disable its endpoints.

The protocol server must perform all endpoint configuration/disabling and wait for those calls to complete before replying to this method. This ensures that the protocol client can report success/failure back to the host (by ACK’ing or STALL’ing the SET_CONFIGURATION request).

Any error returned by this method causes the peripheral controller to stall Control Endpoint 0, signaling a failure to the host (rejecting the SET_CONFIGURATION request).

• error:
  • ZX_ERR_BAD_STATE if the device or function is in an uninitialized state where configuration transitions are invalid (excluding re-configuring an active state).
  • ZX_ERR_INVALID_ARGS if the speed or configuration parameters are invalid.
  • ZX_ERR_NOT_SUPPORTED if the requested speed or configuration is unsupported.
  • ZX_ERR_NO_RESOURCES if endpoint allocation or hardware configuration fails.

Fields

configured: bool

speed: UsbSpeed

responder: UsbFunctionInterfaceSetConfiguredResponder

SetInterface

Called to set an alternate setting for an interface due to a SET_INTERFACE control request.

The protocol server (of [UsbFunctionInterface]) must use [UsbFunction.ConfigureEndpoint] and [UsbFunction.DisableEndpoint] to configure or disable the interface’s endpoints as appropriate for the new alternate setting.

Depending on the alternate setting definition, this transition may require configuring new endpoints (via ConfigureEndpoint), disabling existing endpoints (via DisableEndpoint), or doing both. If an alternate setting does not use any endpoints, no endpoint configuration calls are required.

The protocol server must perform all endpoint configuration/disabling and wait for those calls to complete before replying to this method. This ensures that the protocol client can report success/failure back to the host (by ACK’ing or STALL’ing the SET_INTERFACE request).

Any error returned by this method causes the peripheral controller to stall Control Endpoint 0, signaling a failure to the host (rejecting the SET_INTERFACE request).

• error:
  • ZX_ERR_NOT_SUPPORTED if the alternate setting is not supported.
  • ZX_ERR_INVALID_ARGS if the interface or alt_setting is invalid.
  • Other errors if the function driver fails to configure or disable endpoints for the new setting.

Fields

interface: u8

alt_setting: u8

responder: UsbFunctionInterfaceSetInterfaceResponder

#[non_exhaustive]

_UnknownMethod

An interaction was received which does not match any known method.

Fields

Non-exhaustive enum variants could have additional fields added in future. Therefore, non-exhaustive enum variants cannot be constructed in external crates and cannot be matched against.

ordinal: u64

Ordinal of the method that was called.

control_handle: UsbFunctionInterfaceControlHandle

method_type: MethodType

Implementations

impl UsbFunctionInterfaceRequest

pub fn into_control( self, ) -> Option<(UsbSetup, Vec<u8>, UsbFunctionInterfaceControlResponder)>

pub fn into_set_configured( self, ) -> Option<(bool, UsbSpeed, UsbFunctionInterfaceSetConfiguredResponder)>

pub fn into_set_interface( self, ) -> Option<(u8, u8, UsbFunctionInterfaceSetInterfaceResponder)>

pub fn method_name(&self) -> &'static str

Name of the method defined in FIDL

Trait Implementations

impl Debug for UsbFunctionInterfaceRequest

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.