// 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 zircon.skipblock;

using zx;

// Matches the value of ZBI_PARTITION_GUID_LEN.
const uint32 GUID_LEN = 16;

struct PartitionInfo {
    /// Partition type GUID.
    array<uint8>:GUID_LEN partition_guid;
    /// Describes the read/write size.
    uint64 block_size_bytes;
    /// Describes size of partition in terms of blocks.
    uint32 partition_block_count;
};

struct ReadWriteOperation {
    /// Memory object describing buffer to read into or write from.
    handle<vmo> vmo;
    /// VMO offset in bytes.
    uint64 vmo_offset;
    /// Block # to begin operation from.
    uint32 block;
    /// Number of blocks to read or write.
    uint32 block_count;
};

[Layout = "Simple"]
interface SkipBlock {
    /// Returns information about the skip-block partition.
    ///
    /// The block count can shrink in the event that a bad block is grown. It is
    /// recommended to call this again after a bad block is grown.
    1: GetPartitionInfo() -> (zx.status status, PartitionInfo partition_info);

    /// Reads the specified blocks into the provided vmo.
    2: Read(ReadWriteOperation op) -> (zx.status status);

    /// Erases and writes the specified blocks from the provided vmo.
    ///
    /// In the event that bad block is grown, the partition will shrink and
    /// |bad_block_grown| will be set to true. Since this causes the logical to
    /// physical block map to change, all previously written blocks at logical
    /// addresses after the section being written should be considered corrupted,
    /// and rewritten if applicable.
    3: Write(ReadWriteOperation op) -> (zx.status status, bool bad_block_grown);
};