How to retrieve CPU frequency when cpufreq is missing under 3.16.0-4-arm64?

[Jeffrey Walton <noloader@gmail.com>]

I'm testing on an early Mustang board. Its ARMv8/Aarch64, but it lacks
the mostly standard CRC and Crypto extensions. The tests run in
userland, without any elevation. One of the tests performs some
benchmarks. For accurate results the test script attempts to query the
CPU frequency.

It appears the board is missing 'cpufreq' from
'/sys/devices/system/cpu'. We usually where we find it at, for
example, '/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq'. In
fact, I can't find anything related to frequency or speed:

    $ sudo find /sys/devices/system/cpu -iname  '*freq*'
    $ sudo grep -R freq /sys/devices/system/cpu 2>/dev/null
    $

Apt-get reports the OS is up to date. /etc/apt/sources.list shows
"jessie jessie-updates main non-free contrib"

Another ARMv8 dev board I have runs Linaro and its present. Its also
present under other architectures, like X86 and x86_64.

The OS is:

    $ uname -a
    Linux apm-mustang-8gb #1 SMP Debian 3.16.7-ckt25-2 (2016-04-08)
aarch64 GNU/Linux

Where do we find CPU frequency for ARMv8/Aarch64 under Debian?

Thanks in advance.