roc::Board get/put/oper return codes

The methods accessing the ROC control space, like

• get, put, and oper... in roc::Board
• many set and get methods in classes derived from base::Peripheral

return an int return code. It holds 0 in case the operation succeeded and is non-zero when it failed. In case of failure

• the lower 8 bits contain an error code as defined in roc::Board::operErr and is detailed below
• the upper 24 bits contain an index or step number. This allows to reconstruct the point of failure for list or array operations like roc::Board::operGen.

Use the methods

• roc::Board::operErrCode() to retrieve the error code
• roc::Board::operErrIndex() to retrieve the index value
• roc::Board::operErrBuild() to build a return code
• roc::Board::operErrBuildInc() to modify index part of a return code

The error codes are

• kOperSuccess: success
• kOperAddrErr: invalid address, there is no ROC resource under this address.
• kOperValueErr: invalid value, the value to be written is not allowed in the current state of the ROC or ROC peripheral. Only returned for write type operations.
• kOperStateErr: invalid state, the operation is not allowed in the current state of the ROC or ROC peripheral.
• kOperNetworkErr: network communication error.
• kOperVerifyErr: verify mismatch, a readback after a write operations yielded a value different from the written one. Only returned by dedicated write type operations, the method name often ends in ...Verify.
• kOperBusErr: secondary bus error. This is returned when a field bus operation, like on a I2C bus, failed.