The board sResource has constant, fixed values for the sRsrc_Type entries, so lets look at the sRsrc_Type entry for the more general case of functional sResources.
The sRsrc_Type entry is hiearchical in nature, and has within it four fields. There are broad categories of possible functions a board can perform, and these are represented by the Category field. Within each Category, subset types are defined (these are represented by the cType value). Nested further in the hiearchy, are subset software driver identifiers (the DrvrSW value). And finally, within each DrvrSW entry, are hardware identifiers (the DrvrHW value). The hierarchical relationship looks like:
Category
cType
DrvrSW
DrvrHW
In summary, there are many categories defined. Within each category, certain cTypes are defined (that is, they can be thought of as sub-types of a GIVEN category). Within each cType, certain software driver interfaces are defined (again, a driver interface is defined for a given cType which is in a given Category). For each software driver interface, certain hardware interfaces are defined. Of course, new values for any of these fields may be defined at any time.