sdk/fidl/fuchsia.device.manager/coordinator.fidl

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
library fuchsia.device.manager;

// TODO(teisenbe): Move these interfaces to be internal to the devmgr codebase

using fuchsia.driver.framework as fdf;
using fuchsia.io;
using zx;

/// This has the same structure as zx_device_prop_t.
type DeviceProperty = struct {
    id uint16;
    reserved uint16;
    value uint32;
};

type PropertyValue = strict union {
    1: int_value uint32;
    2: str_value string:STR_LENGTH_MAX;
    3: bool_value bool;
    4: enum_value string:STR_LENGTH_MAX;
};

type DeviceStrProperty = struct {
    key string:STR_LENGTH_MAX;
    value PropertyValue;
};

type DevicePropertyList = struct {
    props vector<DeviceProperty>:PROPERTIES_MAX;
    str_props vector<DeviceStrProperty>:STR_PROPERTIES_MAX;
};

// TODO(bwb): Make this descriptive of binding, not zx_bind_inst_t
// currently a magic bitfield defined in binding.h
type BindInstruction = struct {
    /// bitfield that encodes the operation and execution conditions
    op uint32;
    /// bitfield that encodes the arguments
    arg uint32;
    /// bitfield that encodes debugging information
    debug uint32;
};

// Identifier used to let the devcoordinator describe specific devices during
// composite construction
alias LocalDeviceId = uint64;

/// This definition must match `ZX_DEVICE_NAME_MAX` and is checked by a static assert.
const DEVICE_NAME_MAX uint32 = 31;

/// Maximum number of bytes in a path
// The simple name PATH_MAX collides with a musl #define on c++ bindings.
const DEVICE_PATH_MAX uint32 = 1024;

/// Maximum number of bytes in a device arguments string.
const DEVICE_ARGS_MAX uint32 = 1024;

/// Maximum number of bytes in a metadata payload
const METADATA_BYTES_MAX uint32 = 8192;

/// Maximum number of metadata that can be added to a device
const METADATA_MAX uint32 = 32;

/// Maximum number of properties that can be attached to a device
const PROPERTIES_MAX uint32 = 256;

/// Maximum number of string properties that can be attached to a device
const STR_PROPERTIES_MAX uint32 = 256;

/// Maximum length of a string property key and value.
const STR_LENGTH_MAX uint32 = 255;

/// Maximum number of fragments that a composite device can have
const FRAGMENTS_MAX uint32 = 16;

/// Maximum number of parts that a composite device fragment can have
const DEVICE_FRAGMENT_PARTS_MAX uint32 = 16;

/// Maximum number of instructions in the match program of a device fragment part
const DEVICE_FRAGMENT_PART_INSTRUCTIONS_MAX uint32 = 32;

// Maximum number of instructions in a driver bind program
const BIND_RULES_INSTRUCTIONS_MAX uint32 = 256;

/// Bit flags for device add configuration
type AddDeviceConfig = strict bits : uint32 {
    /// Device can be a fragment in multiple composite devices
    ALLOW_MULTI_COMPOSITE = 0x00000001;
    /// Device should not trigger the auto-bind mechanism
    SKIP_AUTOBIND = 0x00000004;
};

/// A part of a description of a DeviceFragment
type DeviceFragmentPart = struct {
    match_program vector<BindInstruction>:DEVICE_FRAGMENT_PART_INSTRUCTIONS_MAX;
};

/// A piece of a composite device
type DeviceFragment = struct {
    name string:32;
    parts vector<DeviceFragmentPart>:DEVICE_FRAGMENT_PARTS_MAX;
};

/// Metadata that can be added to a device
type DeviceMetadata = struct {
    key uint32;
    data vector<uint8>:METADATA_BYTES_MAX;
};

/// Composite device parts and properties
type CompositeDeviceDescriptor = struct {
    props vector<DeviceProperty>:PROPERTIES_MAX;
    str_props vector<DeviceStrProperty>:STR_PROPERTIES_MAX;
    fragments vector<DeviceFragment>:FRAGMENTS_MAX;
    primary_fragment_index uint32;
    spawn_colocated bool;
    metadata vector<DeviceMetadata>:<METADATA_MAX, optional>;
};

/// Device group parts and properties.
type DeviceGroupDescriptor = struct {
    props vector<DeviceProperty>:PROPERTIES_MAX;
    str_props vector<DeviceStrProperty>:STR_PROPERTIES_MAX;
    fragments vector<fdf.DeviceGroupNode>:MAX;
    spawn_colocated bool;
    metadata vector<DeviceMetadata>:<METADATA_MAX, optional>;
};

/// Protocol for controlling devices in a devhost process from the devcoordinator
protocol DeviceController {
    /// Bind the requested driver to this device.  `driver_path` is informational,
    /// but all calls to BindDriver/CreateDevice should use the same `driver_path`
    /// each time they use a `driver` VMO with the same contents. Returns a `status`
    /// and optionally a channel to the driver's test output. `test_output` will be
    /// not present unless the driver is configured to run its run_unit_tests hook, in
    /// which case the other end of the channel will have been passed to the driver.
    BindDriver(resource struct {
        driver_path string:DEVICE_PATH_MAX;
        driver zx.handle:VMO;
    }) -> (resource struct {
        status zx.status;
        test_output zx.handle:<CHANNEL, optional>;
    });

    /// Give this device a channel to its shadow in another process.
    ConnectProxy(resource struct {
        shadow zx.handle:CHANNEL;
    });

    /// Ask devhost to call the device init hook.
    Init() -> (struct {
        status zx.status;
    });

    /// Ask devhost to unbind this device. On success, the remote end of this
    /// interface channel will close instead of returning a result.
    Unbind() -> (struct {}) error zx.status;

    /// Ask the devhost to complete the removal of this device, which previously had
    /// invoked `ScheduleRemove`. This is a special case that can be removed
    /// once `device_remove` invokes `unbind`.
    CompleteRemoval() -> (struct {}) error zx.status;

    /// Ask devhost to suspend this device, using the target state indicated by `flags`.
    Suspend(struct {
        flags uint32;
    }) -> (struct {
        status zx.status;
    });

    /// Ask devhost to resume this device, using the target system state indicated by
    /// 'target_system_state'.
    Resume(struct {
        target_system_state uint32;
    }) -> (struct {
        status zx.status;
    });

    /// See fuchsia.io.Directory/Open for information.
    Open(resource struct {
        flags fuchsia.io.OpenFlags;
        mode uint32;
        path string:fuchsia.io.MAX_PATH;
        object server_end:fuchsia.io.Node;
    });
};

const FRAGMENT_NAME_MAX uint32 = 32;

type Fragment = struct {
    name string:FRAGMENT_NAME_MAX;
    id LocalDeviceId;
};

type StubDevice = struct {
    protocol_id uint32;
};

type ProxyDevice = resource struct {
    driver_path string:DEVICE_PATH_MAX;
    driver zx.handle:VMO;
    parent_proxy zx.handle:CHANNEL;
    proxy_args string:<DEVICE_ARGS_MAX, optional>;
};

type NewProxyDevice = resource struct {
    incoming_dir client_end:fuchsia.io.Directory;
};

type CompositeDevice = struct {
    fragments vector<Fragment>:FRAGMENTS_MAX;
    name string:DEVICE_NAME_MAX;
};

type DeviceType = resource union {
    /// The device has no parent to communicate with and no driver to load.
    1: stub StubDevice;

    /// The device acts as a proxy for it's parent and talks to it via it's
    /// proxy channel.
    2: proxy ProxyDevice;

    /// The parent device lives in another driver host, and provides a directory
    /// of protocols. This will replace ProxyDevice eventually.
    3: new_proxy NewProxyDevice;

    /// The device is a composite device with several parents, referred to as
    /// fragments. The device aggregates all parent devices together. The order of the
    /// fragments will match the original composite creation request.
    4: composite CompositeDevice;
};

/// Protocol for controlling a driver host process from the driver manager
protocol DriverHostController {
    /// Create a device in the driver host. |type| describes what type of device
    /// is set up, how it communicates with it's parent (if it has one).
    ///
    /// `local_device_id` will be a unique value within the device's devhost
    CreateDevice(resource struct {
        coordinator client_end:Coordinator;
        device_controller server_end:DeviceController;
        type DeviceType;
        local_device_id LocalDeviceId;
    }) -> (struct {
        status zx.status;
    });

    // TODO(fxbug.dev/68309): Currently unimplemented.
    /// Request to restart the driver host. Also restarts all children devices and drivers and
    /// rebinds them once the Driver Host has restarted.
    Restart() -> (struct {
        status zx.status;
    });
};

/// Interface for drivers in driver host to coordinate with the driver
/// manager.
protocol Coordinator {
    /// Record the addition of a new device that can be communicated with via `rpc`.
    /// For binding purposes, it is has properties `props`. `name` and `driver_path`
    /// are informational and used for debugging.  The device will have `protocol_id`
    /// as its primary protocol id.  `args` should only be used for shadowed devices,
    /// and will be forwarded to the shadow device. `client_remote`, if present,
    /// will be passed to the device as an open connection for the client.
    /// On success, the returned `local_device_id` is the identifier assigned by devmgr.
    // TODO(fxb/74654): String properties are unimplemented.
    AddDevice(resource struct {
        coordinator server_end:Coordinator;
        device_controller client_end:DeviceController;
        property_list DevicePropertyList;
        name string:DEVICE_NAME_MAX;
        protocol_id uint32;
        driver_path string:<DEVICE_PATH_MAX, optional>;
        args string:<DEVICE_ARGS_MAX, optional>;
        device_add_config AddDeviceConfig;
        has_init bool;
        inspect zx.handle:<VMO, optional>;
        client_remote zx.handle:<CHANNEL, optional>;
        outgoing_dir client_end:<fuchsia.io.Directory, optional>;
    }) -> (struct {
        local_device_id LocalDeviceId;
    }) error zx.status;

    /// Requests the devcoordinator schedule the removal of this device,
    /// and the unbinding of its children.
    /// If `unbind_self` is true, the unbind hook for this device will also be called.
    ScheduleRemove(struct {
        unbind_self bool;
    });

    /// Requests the devcoordinator schedule the unbinding of this device's children.
    ScheduleUnbindChildren();

    /// Attempt to bind a driver against this device.  If `driver_path` is null,
    /// this will initiate the driver matching algorithm.
    // TODO(teisenbe): Specify the behavior of invoking this multiple times.  I believe
    // the current behavior is a bug.
    BindDevice(struct {
        driver_path string:<DEVICE_PATH_MAX, optional>;
    }) -> (struct {}) error zx.status;

    /// Returns the topological path of this device.
    GetTopologicalPath() -> (struct {
        path string:DEVICE_PATH_MAX;
    }) error zx.status;

    /// Requests that the firmware at the given path be loaded and returned.
    LoadFirmware(struct {
        driver_path string:DEVICE_PATH_MAX;
        fw_path string:DEVICE_PATH_MAX;
    }) -> (resource struct {
        vmo zx.handle:VMO;
        size uint64;
    }) error zx.status;

    /// Retrieve the metadata blob associated with this device and the given key.
    GetMetadata(struct {
        key uint32;
    }) -> (struct {
        data vector<uint8>:METADATA_BYTES_MAX;
    }) error zx.status;

    /// Retrieve the metadata size associated with this device and the given key.
    GetMetadataSize(struct {
        key uint32;
    }) -> (struct {
        size uint64;
    }) error zx.status;

    /// Add metadata blob associated with this device and the given key.
    // TODO(teisenbe): Document the behavior of calling this twice with the same
    // key.  I believe the current behavior results in inaccessible data that is
    // kept around for the lifetime of the device.
    AddMetadata(struct {
        key uint32;
        data vector<uint8>:<METADATA_BYTES_MAX, optional>;
    }) -> (struct {}) error zx.status;

    /// Adds the given composite device.  This causes the driver manager to try to match the
    /// fragments against the existing device tree, and to monitor all new device additions
    /// in order to find the fragments as they are created.
    AddCompositeDevice(struct {
        name string:DEVICE_NAME_MAX;
        comp_desc CompositeDeviceDescriptor;
    }) -> (struct {}) error zx.status;

    /// Adds the given device group. This causes the driver manager to add the device group to
    /// the driver index, and then try to match the nodes against the existing device tree.
    /// All device additions will be monitored to see if they matched to the remaining
    /// unbound nodes.
    AddDeviceGroup(struct {
        name string:DEVICE_NAME_MAX;
        group_desc DeviceGroupDescriptor;
    }) -> (struct {}) error zx.status;
};