[PATCH v2 2/2] Port to new board "VoCore2"

[Daniel Schwierzeck]

On Tue, Jan 7, 2020 at 3:30 PM Mauro Condarelli <mc5686 at mclink.it> wrote:
>
...
> I also have problems with entropy pool in Linux, do you happen to know
> if (and how) MT7628 supports HWRNG?

what problems exactly?

On a embedded device you usually can only add randomness from
interrupts sources to the entropy pool
due to lack of disk or input devices. On a router the most interrupts
are typically generated by drivers
for ethernet and SPI/NAND/MMC controllers. You could use user-space
daemons like haveged [1]
to add more randomness from hardware events.

Also have a look at the documentation in Linux's drivers/char/random.c
for more information, especially
the paragraph "Ensuring unpredictability at system startup".

PS: In my day job (embedded router devices) I use a hash like SHA256
over the U-Boot MTD partition
where also some device specific information like MAC addresses and
serial numbers are stored to generate
the initial seed for the entropy pool on first boot. Afterwards I
manage the random seed over reboots as
described in drivers/char/random.c.

[1] https://linux.die.net/man/8/haveged

-- 
- Daniel