Enum DeviceRequest

pub enum DeviceRequest {
    Start {
        id: u64,
        resolution: Resolution,
        ticks: u64,
        responder: DeviceStartResponder,
    },
    Stop {
        id: u64,
        responder: DeviceStopResponder,
    },
    GetTicksLeft {
        id: u64,
        responder: DeviceGetTicksLeftResponder,
    },
    SetEvent {
        id: u64,
        event: Event,
        responder: DeviceSetEventResponder,
    },
    StartAndWait {
        id: u64,
        resolution: Resolution,
        ticks: u64,
        setup_event: Event,
        responder: DeviceStartAndWaitResponder,
    },
    StartAndWait2 {
        id: u64,
        resolution: Resolution,
        ticks: u64,
        setup_keep_alive: EventPair,
        responder: DeviceStartAndWait2Responder,
    },
    GetProperties {
        responder: DeviceGetPropertiesResponder,
    },
    _UnknownMethod {
        ordinal: u64,
        control_handle: DeviceControlHandle,
        method_type: MethodType,
    },
}

A driver providing high resolution timers support. This API is intended for timers that are provided by hardware separate from the CPU For instance this driver may abstract hardware provided by an SoC.

Variants

Start

Start the timer id to expire after ticks.

If ticks is 0 then the timer will expire in 0 ticks (immediately). If the timer id was already started, then the previous Start is canceled and the driver will restart the timer. Note that this may race with the expiration of the previous timer, for instance the notification process may be already started and a new Start call won’t be able to stop a notification that is already in flight. If the specified id is invalid, then this call will return INVALID_ARGS. If the specified resolution is not supported per the resolutions provided by GetProperties, then this call will return INVALID_ARGS. If the specified ticks is beyond the range supported for the timer as provided by GetProperties, then this call will return INVALID_ARGS. If the driver encounters an internal error, then this call will return INTERNAL_ERROR.

Fields

id: u64

resolution: Resolution

ticks: u64

responder: DeviceStartResponder

Stop

Stops the timer id.

Note that this may race with the expiration of the timer, for instance notification via an event set with SetEvent may be already in flight. If the specified id is invalid, then this call will return INVALID_ARGS. If the driver encounters an internal error, then this call will return INTERNAL_ERROR.

Fields

id: u64

responder: DeviceStopResponder

GetTicksLeft

Get the current time in ticks left in timer id until expiration.

If the specified id is invalid, then this call will return INVALID_ARGS.

Fields

id: u64

responder: DeviceGetTicksLeftResponder

SetEvent

Sets a Zircon Event to be notified of the timer expiration.

The timer expiration will be notified via the ZX_EVENT_SIGNALED signal. The client is responsible for clearing the ZX_EVENT_SIGNALED signal. Any previously event set for the specific id is replaced. Note that this may race with the event signaling from the expiration of a timer already started. To guarantee that an event is delivered upon timer expiration, this method must be called before calling Start.

If the specified id is invalid, then this call will return INVALID_ARGS. If this method is not supported for the given id, then this call will return NOT_SUPPORTED. If the driver encounters an internal error, then this call will return INTERNAL_ERROR.

Fields

id: u64

event: Event

responder: DeviceSetEventResponder

StartAndWait

Start the timer id to expire after ticks and waits until the timer expires with support for preventing suspension via the Power Framework.

The driver will signal the setup_event event once the timer has been setup using the ZX_EVENT_SIGNALED signal. This allows a client to know that it is safe to allow the system to suspend. The client is responsible for clearing this event.

The driver will not respond to this call (hang) until the timer has triggered. Calling Stop on the timer will abort this call and return CANCELED. Note that this may race with the expiration of the timer.

A driver supporting this call must be able to get a lease on a power element that keeps the system from suspending. This lease is returned to the client via the keep_alive LeaseToken channel field. When keep_alive is closed, then the driver lease keeping the system from suspending will be dropped. Hence, to guarantee that the system is not suspended by the Power Framework a client must either keep this keep_alive token for as long as the system needs to not suspend, or a client must get its own lease from the Power Framework to prevent suspension before it drops keep_alive.

If the specified id is invalid, then this call will return INVALID_ARGS. If this method is not supported for the given id, then this call will return NOT_SUPPORTED. If the driver does not have a keep_alive token to provide to the client, then this call will return BAD_STATE. If the driver encounters an internal error, then this call will return INTERNAL_ERROR.

Fields

id: u64

resolution: Resolution

ticks: u64

setup_event: Event

responder: DeviceStartAndWaitResponder

StartAndWait2

Start timer id and wait for it to expire after ticks ticks.

The driver will not respond to this call (hang) until the timer has triggered. Calling Stop on the timer will abort this call and return CANCELED. Note that this may race with the expiration of the timer.

This method keeps the system awake (prevents suspension) while the timer is setup using the mandatory passed-in setup_keep_alive LeaseToken. When the timer expires this method returns a second expiration_keep_alive LeaseToken to prevent suspension at the time of expiration. These keep alive wake lease tokens are provided by the Power Framework’s System Activity Governor. A driver supporting this call must be able to get expiration_keep_alive from System Activity Governor.

When expiration_keep_alive is closed, then this driver created wake lease keeping the system from suspending at the time of the timer expiration is dropped. Hence, to guarantee that the system is not suspended by the Power Framework a client must either keep this expiration_keep_alive for as long as the system needs to stay awake, or a client must get its own wake lease from the Power Framework before it drops expiration_keep_alive to prevent suspension.

Errors:

• INVALID_ARGS: The specified id is invalid.
• NOT_SUPPORTED: This method is not supported for the given id.
• BAD_STATE: The driver is in a bad state, for instance it does not have an expiration_keep_alive token to provide to the client.
• INTERNAL_ERROR: The driver encountered an internal error.

Fields

id: u64

resolution: Resolution

ticks: u64

setup_keep_alive: EventPair

responder: DeviceStartAndWait2Responder

GetProperties

Get driver properties.

Fields

responder: DeviceGetPropertiesResponder

_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: DeviceControlHandle

method_type: MethodType

Implementations

impl DeviceRequest

pub fn into_start(self) -> Option<(u64, Resolution, u64, DeviceStartResponder)>

pub fn into_stop(self) -> Option<(u64, DeviceStopResponder)>

pub fn into_get_ticks_left(self) -> Option<(u64, DeviceGetTicksLeftResponder)>

pub fn into_set_event(self) -> Option<(u64, Event, DeviceSetEventResponder)>

pub fn into_start_and_wait( self, ) -> Option<(u64, Resolution, u64, Event, DeviceStartAndWaitResponder)>

pub fn into_start_and_wait2( self, ) -> Option<(u64, Resolution, u64, EventPair, DeviceStartAndWait2Responder)>

pub fn into_get_properties(self) -> Option<DeviceGetPropertiesResponder>

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

Name of the method defined in FIDL

Trait Implementations

impl Debug for DeviceRequest

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

Formats the value using the given formatter.