having used the AM3358 extensively, the TRM is not complete. There are some pretty important and complex systems that have literally no documentation at all in the TRM, not to mention the large number of quirks and small details that you can only pick up from a scattering of other areas (including a wiki that TI deleted some years ago). It is, however, miles better than the documentation available for most SOCs.

Agreed. The actual technical writing portion of the TRM leaves much to be desired.