smbuslib.c

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/**
  Executes an SMBUS read data word command.

  Executes an SMBUS read data word command on the SMBUS device specified by SmBusAddress.
  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
  The 16-bit value read from the SMBUS is returned.
  If Status is not NULL, then the status of the executed command is returned in Status.
  If Length in SmBusAddress is not zero, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().
  
  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The byte read from the SMBUS.

**/
UINT16
EFIAPI
SmBusReadDataWord (
  IN  UINTN          SmBusAddress,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  UINT16  Word;

  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)    == 0);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  InternalSmBusExec (EfiSmbusReadWord, SmBusAddress, 2, &Word, Status);
  
  return Word;
}

/**
  Executes an SMBUS write data word command.

  Executes an SMBUS write data word command on the SMBUS device specified by SmBusAddress.
  The 16-bit value specified by Value is written.
  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
  Value is returned.
  If Status is not NULL, then the status of the executed command is returned in Status.
  If Length in SmBusAddress is not zero, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().

  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Value           The 16-bit value to write.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The parameter of Value.

**/
UINT16
EFIAPI
SmBusWriteDataWord (
  IN  UINTN          SmBusAddress,
  IN  UINT16         Value,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  UINT16  Word;

  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)    == 0);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  Word = Value;
  InternalSmBusExec (EfiSmbusWriteWord, SmBusAddress, 2, &Word, Status);

  return Value;
}

/**
  Executes an SMBUS process call command.

  Executes an SMBUS process call command on the SMBUS device specified by SmBusAddress.
  The 16-bit value specified by Value is written.
  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
  The 16-bit value returned by the process call command is returned.
  If Status is not NULL, then the status of the executed command is returned in Status.
  If Length in SmBusAddress is not zero, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().

  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Value           The 16-bit value to write.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The 16-bit value returned by the process call command.

**/
UINT16
EFIAPI
SmBusProcessCall (
  IN  UINTN          SmBusAddress,
  IN  UINT16         Value,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)    == 0);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  InternalSmBusExec (EfiSmbusProcessCall, SmBusAddress, 2, &Value, Status);
  
  return Value;
}

/**
  Executes an SMBUS read block command.

  Executes an SMBUS read block command on the SMBUS device specified by SmBusAddress.
  Only the SMBUS slave address and SMBUS command fields of SmBusAddress are required.
  Bytes are read from the SMBUS and stored in Buffer.
  The number of bytes read is returned, and will never return a value larger than 32-bytes.
  If Status is not NULL, then the status of the executed command is returned in Status.
  It is the caller's responsibility to make sure Buffer is large enough for the total number of bytes read.
  SMBUS supports a maximum transfer size of 32 bytes, so Buffer does not need to be any larger than 32 bytes.
  If Length in SmBusAddress is not zero, then ASSERT().
  If Buffer is NULL, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().

  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Buffer          Pointer to the buffer to store the bytes read from the SMBUS.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The number of bytes read.

**/
UINTN
EFIAPI
SmBusReadBlock (
  IN  UINTN          SmBusAddress,
  OUT VOID           *Buffer,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  ASSERT (Buffer != NULL);
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress)    == 0);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  return InternalSmBusExec (EfiSmbusReadBlock, SmBusAddress, 0x20, Buffer, Status);
}

/**
  Executes an SMBUS write block command.

  Executes an SMBUS write block command on the SMBUS device specified by SmBusAddress.
  The SMBUS slave address, SMBUS command, and SMBUS length fields of SmBusAddress are required.
  Bytes are written to the SMBUS from Buffer.
  The number of bytes written is returned, and will never return a value larger than 32-bytes.
  If Status is not NULL, then the status of the executed command is returned in Status.  
  If Length in SmBusAddress is zero or greater than 32, then ASSERT().
  If Buffer is NULL, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().

  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  Buffer          Pointer to the buffer to store the bytes read from the SMBUS.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The number of bytes written.

**/
UINTN
EFIAPI
SmBusWriteBlock (
  IN  UINTN          SmBusAddress,
  OUT VOID           *Buffer,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  UINTN  Length;

  ASSERT (Buffer != NULL);
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress) >= 1);
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress) <= 32);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  Length = SMBUS_LIB_LENGTH (SmBusAddress);
  return InternalSmBusExec (EfiSmbusWriteBlock, SmBusAddress, Length, Buffer, Status);
}

/**
  Executes an SMBUS block process call command.

  Executes an SMBUS block process call command on the SMBUS device specified by SmBusAddress.
  The SMBUS slave address, SMBUS command, and SMBUS length fields of SmBusAddress are required.
  Bytes are written to the SMBUS from WriteBuffer.  Bytes are then read from the SMBUS into ReadBuffer.
  If Status is not NULL, then the status of the executed command is returned in Status.
  It is the caller's responsibility to make sure ReadBuffer is large enough for the total number of bytes read.
  SMBUS supports a maximum transfer size of 32 bytes, so Buffer does not need to be any larger than 32 bytes.
  If Length in SmBusAddress is zero or greater than 32, then ASSERT().
  If WriteBuffer is NULL, then ASSERT().
  If ReadBuffer is NULL, then ASSERT().
  If any reserved bits of SmBusAddress are set, then ASSERT().

  @param  SmBusAddress    Address that encodes the SMBUS Slave Address,
                          SMBUS Command, SMBUS Data Length, and PEC.
  @param  WriteBuffer     Pointer to the buffer of bytes to write to the SMBUS.
  @param  ReadBuffer      Pointer to the buffer of bytes to read from the SMBUS.
  @param  Status          Return status for the executed command.
                          This is an optional parameter and may be NULL.

  @return The number of bytes written.

**/
UINTN
EFIAPI
SmBusBlockProcessCall (
  IN  UINTN          SmBusAddress,
  IN  VOID           *WriteBuffer,
  OUT VOID           *ReadBuffer,
  OUT RETURN_STATUS  *Status        OPTIONAL
  )
{
  UINTN   Length;

  ASSERT (WriteBuffer != NULL);
  ASSERT (ReadBuffer  != NULL);
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress) >= 1);
  ASSERT (SMBUS_LIB_LENGTH (SmBusAddress) <= 32);
  ASSERT (SMBUS_LIB_RESEARVED (SmBusAddress) == 0);

  Length = SMBUS_LIB_LENGTH (SmBusAddress);
  //
  // Assuming that ReadBuffer is large enough to save another memory copy.
  //
  ReadBuffer = CopyMem (ReadBuffer, WriteBuffer, Length);
  return InternalSmBusExec (EfiSmbusBWBRProcessCall, SmBusAddress, Length, ReadBuffer, Status);
}