How to access files on the SD Card from a bare metal application?

Hello;

I am currently writing a C program, in a bare metal approach (I need bare metal due performance restrictions), currently I am able to transfer data from the C program to the FPGA . The board that I'm using the Altera Cyclone V DE1 - SoC.

Next step, is to access a file on the SD Card from the HPS and then transfer that information to the FPGA. However, I can't find any documentation or examples to do this process. Do I need to write a SD Card driver from scratch? Is there any example available?

EDIT: what i need is a way to access files that are stored on the SD card from the bare metal C code.

Thanks in advance.