You may start from the circuit shown in the attached figure. The load in the figure can be replaced with DC Brushed Motor. The output of the current sensing circuit is connected to an ADC before it's fed to microcontroller or DSP that acts as a current controller.
Depending on how complicated circuit do you have in mind, you have several options starting from simple current limit circuit based on 2 transistors, next stage using op-amps,...., microcontrollers.
You may try one section of a circuit attached below: