Cyclone V HPS CPU frequency

How do I query and/or set the core frequency for the Cyclone V embedded SoC ARM CPU running Angstrom Linux?

I'm using a DE10-Nano board with a Linux console BSP from Terasic. In /proc/cpuinfo, I only see a mention of "200.00 BogoMIPS". Coupled with a mention of 2.5 MIPS/MHz in the HPS reference manual, this would put me at 80 MHz, which seems rather low. None of the other normal ways of querying the frequency work (there's no lscpu, or lshw, or /sys/devices/system/cpu/cpu0/cpufreq).

In Platform Designer, I have the "MPU clock frequency" at the default value of 800 MHz. At boot-up, it says, among other things, "CLOCK: MPU clock 925 MHz". I tried to rebuild and upload the preloader: ran the BSP editor, went into <project>/software/spl_bsp, ran "make", produced a "preloader-mkpimage.bin", and copied it onto /dev/mmcblk0p3. It changed the value displayed for "CLOCK: MPU clock" from 925 to 800, but had no effect on MIPS.