// Copyright 2021 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.tpm;

using zx;

/// Arbitrarily large value which should be enough to handle any vendor
/// commands.
const MAX_VENDOR_COMMAND_LEN uint32 = 65535;

/// TPM response codes are fairly complex.
/// See Section 6.6, "TPM_RC (Response Codes)" of the "Trusted Platform Module Library
/// Part 2: Structures" for more information on how they should be interpreted.
/// The TPM may return vendor-defined error codes or set various bits in the
/// error to provide more information about the nature of the error.
alias TpmRc = uint16;

protocol TpmDevice {
    /// Get the TPM's device ID, vendor ID, and revision ID.
    GetDeviceId() -> (struct {
        vendor_id uint16;
        device_id uint16;
        revision_id uint8;
    }) error zx.status;

    /// Execute a vendor command.
    /// Returns ZX_ERR_BUFFER_TOO_SMALL if the TPM responded with data that
    /// wouldn't fit in the response buffer.
    ExecuteVendorCommand(struct {
        command_code uint16;
        data vector<uint8>:MAX_VENDOR_COMMAND_LEN;
    }) -> (struct {
        result TpmRc;
        data vector<uint8>:MAX_VENDOR_COMMAND_LEN;
    }) error zx.status;
};