tlbmc/deterministic_bmc/i2c_walker/i2c_walker_interface.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_DETERMINISTIC_BMC_I2C_WALKER_I2C_WALKER_INTERFACE_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_DETERMINISTIC_BMC_I2C_WALKER_I2C_WALKER_INTERFACE_H_
#include <cstdint>
#include <optional>
#include <ostream>
#include <string>
#include <tuple>
#include <vector>

#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/str_cat.h"

namespace deterministic_bmc {

// Interface for walking the I2C bus. Implementations of this interface are
// expected to be thread-safe.
class I2cWalkerInterface {
 public:
  struct HardwareInfo {
    // The resolved logical bus number of the i2c device. std::nullopt if any
    // error occurred during the i2c walk.
    std::optional<uint32_t> logical_bus;
    // The address of the i2c device.
    uint32_t address;
    // The barepath of the i2c device.
    std::string barepath;
    // The part number of the i2c device.
    std::string part_number;
    // The serial number of the i2c device.
    std::string serial_number;

    // If not_found_info is nullopt, it means the i2c device is found and the
    // HardwareInfo is valid.
    // If not_found_info is not nullopt, it means the i2c device is expected to
    // be valid but encountered error during i2c walk on sysfs of the real
    // machine. This information will be used to indicate missing expected i2c
    // devices.
    struct NotFoundInfo {
      // The status of the error. We will use NotFoundError to indicate i2c
      // sysfs work issues. The message in the status will be more informative
      // about what actually went wrong. Currently, major issues are:
      // 1. Root bus or mux path does not exist.
      // 2. Mux model mismatch.
      // 3. Invalid symlink: symlink file itself does not exist or not a
      // symlink.
      // 4. fail to read symlink.
      // 5. Invalid bus id.
      absl::Status status;
      uint32_t physical_bus;
      std::string mux_model;
      uint32_t mux_address;
      uint32_t channel;

      friend std::ostream& operator<<(std::ostream& os,
                                      const NotFoundInfo& info);

      bool operator==(const NotFoundInfo& other) const {
        return std::tie(status, physical_bus, mux_model, mux_address,
                        channel) == std::tie(other.status, other.physical_bus,
                                             other.mux_model, other.mux_address,
                                             other.channel);
      }
    };

    std::optional<NotFoundInfo> not_found_info;

    friend std::ostream& operator<<(std::ostream& os, const HardwareInfo& info);

    bool operator==(const HardwareInfo& other) const {
      return std::tie(logical_bus, address, barepath, part_number,
                      serial_number, not_found_info) ==
             std::tie(other.logical_bus, other.address, other.barepath,
                      other.part_number, other.serial_number,
                      other.not_found_info);
    }
  };

  virtual ~I2cWalkerInterface() = default;
  // Read the physical i2c topology information from the uhmm offline config and
  // return a list of i2c devices with logical addresses.
  virtual absl::StatusOr<std::vector<HardwareInfo>> GetLogicalI2cAddresses()
      const = 0;
};

// The ostream operator for NotFoundInfo.
inline std::ostream& operator<<(
    std::ostream& os,
    const I2cWalkerInterface::HardwareInfo::NotFoundInfo& info) {
  os << "physical_bus: " << info.physical_bus
     << ", mux_model: " << info.mux_model
     << ", mux_address: " << info.mux_address << ", channel: " << info.channel
     << ", status: " << info.status;
  return os;
}

// The ostream operator for HardwareInfo.
inline std::ostream& operator<<(std::ostream& os,
                                const I2cWalkerInterface::HardwareInfo& info) {
  os << "logical_bus: "
     << (info.logical_bus.has_value() ? absl::StrCat(info.logical_bus.value())
                                      : "no_resolved_bus")
     << ", address: " << info.address << ", barepath: " << info.barepath
     << ", part_number: " << info.part_number
     << ", serial_number: " << info.serial_number << ", not_found_info: ";

  if (info.not_found_info.has_value()) {
    os << info.not_found_info.value();
  } else {
    os << "N/A";
  }

  return os;
}

}  // namespace deterministic_bmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_DETERMINISTIC_BMC_I2C_WALKER_I2C_WALKER_INTERFACE_H_