[U-Boot] Configuring BRGs and BRG input clock on an MPC875

Hello, I thought I'd ask here before I go and make a mess of my code: what's the easiest way to configure my board to have SMC1 use BRG1, SCC4 use BRG2, and make my BRG1 and BRG2 use CLK2 as an input clock?

I looked over the code and it looked like most of this is hard-coded in the "serial.c" file to use BRG1 for everything and I think to use BRGCLK as the BRG clock source ("serial_setdivisor" function).

My board is similar to the EP88xc by the way.

Thanks, Mikhail Zaturenskiy