sw/host/spiflash/verilator_spi_interface.h

// Copyright lowRISC contributors.
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0

#ifndef _F_SPIFLASH_VERILATOR_SPI_INTERFACE_H__
#define _F_SPIFLASH_VERILATOR_SPI_INTERFACE_H__

#include <string>

#include "spi_interface.h"

namespace opentitan {
namespace spiflash {

// Implements SPI interface for an OpenTitan instance running on Verilator.
// The OpenTitan Verilator model provides a file handle for the SPI device
// interface. This class sends ands recevies data to the device handle, and
// adds synchronication delays between writes and reads.
// This class is not thread safe.
class VerilatorSpiInterface : public SpiInterface {
 public:
  // Constructs instance pointing to the |spi_filename| file path.
  explicit VerilatorSpiInterface(std::string spi_filename)
      : spi_filename_(spi_filename), fd_(-1) {}

  // Closes the internal file handle used to communicate with the SPI device.
  ~VerilatorSpiInterface() override;

  // Initialize interface.
  bool Init() final;

  // Transmit bytes from |tx| buffer and read data back onto |rx| buffer. The
  // number of bytes are defined by |size|.
  bool TransmitFrame(const uint8_t *tx, uint8_t *rx, size_t size) final;

 private:
  std::string spi_filename_;
  int fd_;
};

}  // namespace spiflash
}  // namespace opentitan

#endif  // _F_SPIFLASH_VERILATOR_SPI_INTERFACE_H__