ChibiOS Free Embedded RTOS

• The following example code snippet wouldn't work(assume BaseSensor has a data variable called 'msg_t stateSensor') (just for illustration):
  In hal_sensors.h:
  

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  /**
   * @brief   @p BaseSensor specific data.
   * @note    It is empty because @p BaseSensor is only an interface
   *          without implementation.
   */
  #define _base_sensor_data \
    msg_t stateSensor;
  

  And in main.c:
  

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    LIS302DLDriver derivedAccelerometerObject = {0};
    LIS302DLDriver * derivedAccelerometerPointer = &derivedAccelerometerObject;
    BaseSensor * baseAccelerometerPointer = (BaseSensor *)&derivedAccelerometerObject;
    derivedAccelerometerPointer->stateSensor = 1;
    msg_t stateViewedFromBaseAccelerometerPointer = baseAccelerometerPointer->stateSensor;
  

  In above snippet, stateViewedFromBaseAccelerometerPointer doesn't get updated with value of '1'.
  
  
• A potential solution would be is to define class heirarchy of hal_sensors and it's derived forms as:
  

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  /**
   * @brief   Base sensor class.
   * @details This class represents a generic blocking unbuffered sequential
   *          data stream.
   */
  typedef struct {
    /** @brief Virtual Methods Table.*/
    const struct BaseSensorVMT *vptr;
    _base_sensor_data
  } BaseSensor;
  
  /**
   * @brief   Base accelerometer class.
   * @details This class represents a generic a generic accelerometer.
   */
  typedef struct {
    /** @brief Virtual Methods Table.*/
    const struct BaseAccelerometerVMT *vptr;
    _base_sensor_data
  } BaseAccelerometer;
  
  
  /**
   * @extends BaseAccelerometer
   *
   * @brief   LIS302DL 3-axis accelerometer class.
   * @details This class extends @p BaseAccelerometer by adding physical
   *          driver implementation.
   */
  struct LIS302DLDriver {
    /** @brief LIS302DL Virtual Methods Table. */
    const struct LIS302DLVMT *vptr;
    _lis302dl_data
  };
  

  And then the macro definitions for function call helpers as:
  

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  /**
   * @name    Macro Functions (BaseSensor)
   * @{
   */
  /**
   * @brief   Sensors get channels number.
   *
   * @param[in] ip        pointer to a @p BaseSensor or derived class.
   * @return              The number of channels of the BaseSensor
   *
   * @api
   */
  #define sensorGetChannelNumber(ip) (ip)->vptr->get_channels_number(ip)
  
  /**
   * @brief   Sensors read raw data.
   *
   * @param[in] ip        pointer to a @p BaseSensor or derived class.
   * @param[in] dp        pointer to a data array.
   * 
   * @return              The operation status.
   * @retval MSG_OK       if the function succeeded.
   * @retval MSG_RESET    if one or more errors occurred.
   *
   * @api
   */
  #define sensorReadRaw(ip, dp) (ip)->vptr->read_raw(ip, dp)
  

  
  ...similarly for all derived classes of BaseSensor

Giovanni wrote:Hi,

About flash, thet code I am looking at is different from what you posted.

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#define _jesd216_flash_methods                                              \
  _base_flash_methods                                                       \
  _jesd216_flash_methods_alone

struct JESD215FlashVMT {
  _jesd216_flash_methods
};

#define _jesd216_flash_data                                                 \
  _base_flash_data

typedef struct {
  /** @brief Virtual Methods Table.*/
  const struct JESD215FlashVMT *vmt;
  _jesd216_flash_data
} JESD215Flash;

The offset of _jesd216_flash_data does not change, there is always just one pointer before it.

RoccoMarco is looking into the other problem.

Giovanni

Giovanni wrote:Hi,

We identified various problems in EX related to multiple inheritance, we are working on it, thanks for finding.

Giovanni

RoccoMarco wrote:Fixed on trunk and backported to 17.6.4 as Bug #915.

struct LIS302DLDriver {
  const struct LIS302DLAccelerometerVMT *vmt_accelerometer;
  _base_accelerometer_data
  _lis302dl_data
};