[LEDE-DEV] CPU locked at lowest frequency on BCM2078 targets

[Bryan Mayland]

Hello, I work on an open source project which uses the Raspberry Pi
with LEDE as the host board. I've noticed that the kernel config does
not include the BCM2835 cpufreq driver and therefore the CPU remains
locked at the frequency set by the bootloader. This severely degrades
the performance of these devices as the bootloader sets the CPU at the
lowest frequency. I've run some nbench-byte benchmarks on bcm2708 and
bcm2709 (32-bit) platforms:

Raspberry Pi Zero W (2708) - Standard LEDE
TEST                : Iterations/sec.  : Old Index   : New Index
                    :                  : Pentium 90* : AMD K6/233*
--------------------:------------------:-------------:------------
NUMERIC SORT        :          231.72  :       5.94  :       1.95
STRING SORT         :          6.6755  :       2.98  :       0.46
- With cpufreq enabled (ondemand scaler)
NUMERIC SORT        :          322.87  :       8.28  :       2.72
STRING SORT         :           9.561  :       4.27  :       0.66

Raspberry Pi 3 (2709) - Standard LEDE
TEST                : Iterations/sec.  : Old Index   : New Index
                    :                  : Pentium 90* : AMD K6/233*
--------------------:------------------:-------------:------------
NUMERIC SORT        :             344  :       8.82  :       2.90
STRING SORT         :          9.7163  :       4.34  :       0.67
- With cpufreq enabled (ondemand scaler)
NUMERIC SORT        :          683.62  :      17.53  :       5.76
STRING SORT         :          19.446  :       8.69  :       1.34

Can we get cpufreq, ondemand scaler, and default=ondemand for this
platform / two targets? If needed I can submit a patch / signoff, or
if there is a reason this should not be done I'd love to start a
discussion about it.

--
Bryan Mayland