As posted by nndhawan@gmail.com, you dont need to recompile your kernel (or u-boot) to do pinmuxing, you can just jump over kernel and do it directly (devmem2 is an option) by writing the register memory, as this:
int fd = open("/dev/mem", O_RDWR | O_SYNC);
volatile ulong pinMux = (ulong) mmap(NULL, 0x10000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x48000000);
pinMux[pinOffset/4] = muxmodeAndOtherSettings; (as 0x00040004 for mode4, both pins on this register)
I think I have the pin muxing working via the "xora kernel work
flow". I've tested this using the Linux /sys/class/gpio export method
and am able to toggle the gpio pins. Now I think I am back to
figuring out the secret to access via the DSP. Do I need to adjust
the memory map, or adjust my accesses via a changed memory map? Do I
need to disable things in Linux that are conflicting with the DSP?