// Copyright 2020 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.hardware.acpi;
using zx;

const uint32 MAX_ACPI_TABLE_ENTRIES = 512;

/// An ACPI table name signature. This consists of four ASCII characters.
using AcpiTableSignature = array<uint8>:4;

/// Metadata about an ACPI table entry.
struct TableInfo {
    /// Name of the table. There may be multiple tables with the same name.
    AcpiTableSignature name;

    /// The size of the table, in bytes.
    uint32 size;
};

/// Defines access to raw system ACPI data.
///
/// This interface is intended only for low-level debugging tools.
protocol Acpi {
    /// Return the list of ACPI tables present in the system.
    ListTableEntries() -> (vector<TableInfo>:MAX_ACPI_TABLE_ENTRIES entries) error zx.status;

    /// Write the raw content of the named ACPI table into the given VMO.
    ///
    /// Some systems may have multiple ACPI tables with the same name ("SSDT" is
    /// a commonly repeated table, for example). |instance| is used to specify
    /// which instance of the named table to return. A value of |n| returns the
    /// |n|'th occurence. If only one table with the given name is present,
    /// |instance| should be 0.
    ///
    /// On success, returns the number of bytes written into result.
    ReadNamedTable(AcpiTableSignature name, uint32 instance, handle<vmo> result)
        -> (uint32 size) error zx.status;
};