nearly-working support for cpufreq on 2004 iBook G4 with 7447A cpu

John Steele Scott toojays at
Mon May 31 18:37:32 EST 2004

On Mon, 31 May 2004 01:19 pm, Benjamin Herrenschmidt wrote:
> Ok, that's weird, I don't see the same kind of clock chip on i2c as
> the previous model had... Can you check the exact dividers programmed
> on the CPU and redo the calculation based on the bus frequency ?


At boot: HID1=80414c80 => PLL_CFG=10100, i.e. 4:1 core multiplier

After clearing DFS, HID1=80018c80 => PLL_CFG=11000, i.e. 8:1 core multiplier

I decoded the PLL values using the table on page 31 of Moto's MPC7447AEC.pdf.

bash-2.05b$ cat /proc/device-tree/clock-frequency  | xxd
0000000: 07ef 4679                                ..Fy
bash-2.05b$ python -c 'print "%d" % 0x07ef4679'

Looks sensible to me. Does it give you any clues?



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