// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef MPACT_RISCV_RISCV_RISCV32_HTIF_SEMIHOST_H_
#define MPACT_RISCV_RISCV_RISCV32_HTIF_SEMIHOST_H_

#include <cstdint>
#include <string>

#include "absl/container/flat_hash_map.h"
#include "absl/functional/any_invocable.h"
#include "mpact/sim/generic/data_buffer.h"
#include "mpact/sim/util/memory/memory_interface.h"
#include "mpact/sim/util/memory/memory_watcher.h"

// This class implements semi-hosting for code generated by the RiscV tools
// in third_party/chipyard. Instead of using breakpoint or sys call instructions
// the tools assume memory watchpoints.

namespace mpact {
namespace sim {
namespace riscv {

class RiscV32HtifSemiHost {
 public:
  using HaltCallback = absl::AnyInvocable<void()>;
  using ErrorCallback = absl::AnyInvocable<void(std::string)>;

  // A struct for the set of addresses used in this semi-hosting.
  struct SemiHostAddresses {
    uint64_t tohost_ready;
    uint64_t tohost;
    uint64_t fromhost_ready;
    uint64_t fromhost;
  };

  RiscV32HtifSemiHost(util::MemoryWatcher *watcher,
                      util::MemoryInterface *memory,
                      const SemiHostAddresses &magic_addresses);

  RiscV32HtifSemiHost(util::MemoryWatcher *watcher,
                      util::MemoryInterface *memory,
                      const SemiHostAddresses &magic_addresses,
                      HaltCallback halt_callback, ErrorCallback error_callback);

  ~RiscV32HtifSemiHost();

  // Set magic addresses.
  void SetMagicAddresses(const SemiHostAddresses &magic_addresses);
  // Set the halt callback.
  void SetHaltCallback(HaltCallback halt_callback);
  // Set the error callback.
  void SetErrorCallback(ErrorCallback error_callback);
  // Callback function used by memory watchpoint class.
  void StoreEvent(uint64_t address, int size);

 private:
  // A local data buffer factory.
  generic::DataBufferFactory db_factory_;
  HaltCallback halt_callback_;
  ErrorCallback error_callback_;
  // Memory watcher.
  util::MemoryWatcher *watcher_;
  // Memory interface (bypassing the watchpoints).
  util::MemoryInterface *memory_;
  SemiHostAddresses magic_addresses_;
  // File descriptor map.
  absl::flat_hash_map<int, int> fd_map_;
};

}  // namespace riscv
}  // namespace sim
}  // namespace mpact

#endif  // MPACT_RISCV_RISCV_RISCV32_HTIF_SEMIHOST_H_