i.MX8 series contains internal HiFi4 DSP. It is targeted for Audio related signal
processing. SOF (Sound Open Firmware) is open source audio DSP firmware,
driver and SDK. This document introduces basic theory about IIR/FIR digital
filters, how to design IIR/FIR digital filters and the Equalizer filters
implementation by SOF. After that, the document also describes how HiFi4
DSP MAC engine accelerate the EQ filters calculation.
