This is what I see in my installion of BIOSPSP (admittedly it is old):
pspdrivers_01_30_01\packages\ti\pspiom\cslr\soc_C6747.h
... #define CSL_SYSCLK_1_FREQ (300000000) ... #define CSL_SPI_0_MODULE_FREQ (CSL_SYSCLK_2_FREQ) #define CSL_SPI_1_MODULE_FREQ (CSL_SYSCLK_2_FREQ) ...
The SPI library project is here:
pspdrivers_01_30_01\packages\ti\pspiom\spi\build\C6747\ccs3\spi.pjt