when you install SoC EDS there are some examples of baremetal located in <quartus version>\embedded\examples\software. If i am not mistaken, these should be generic to all boards. You can find more examples here: https://www.altera.com/support/support-resources/design-examples.html#socdesignexamples
Note that these are mostly called hwlibs as they uses the Altera-provided HAL. For some of these examples (especially the ones that interfaced to outside world) I believe you will need to use your own preloader (rather than the default one for the CV SoC development kit)