ref: 5ebb1a29d8250027e8b7f2287f3bfa3a6f3d13ac
dir: /sys/src/9/teg2/notes/clks/
see §5.4.40 (p.142) pllx_* (2 regs) out of u-boot, these are the settings: --- pllx base 0x4003e80c: enabled, no locked divp == 0 (post divider == 2^0 == 1) divn == 1000 (feedback divider) divm == 12 (input divider) misc 0x100: pllx_cpcon == 1 [ should be 12 ] super cclk divider 0x80000000: enabled dividend == 0 (thus 1) divisor == 0 (thus 1) super sclk divider 0x0: disabled dividend == 0 (thus 1) divisor == 0 (thus 1) ---