wwaites / cryptocape

Beaglebone Black + Cryptocape support in FreeBSD

FreeBSD Beaglebone Black + Cryptocape

This directory contains materials for getting some of the hardware on the Cryptocape working with FreeBSD. It might also be a useful starting point for others accessing some of the hardware features of the Beaglebone which are not enabled by default.

To get some of the hardware to work, the pin multiplexer must be configured. This is done, for example, to enable UART4 to communicate with the on-board ATMega328p. The way this is done has changed somewhat between FreeBSD 10 and 11 and now the registers are written in the DTS simply by their number. The correct number can be found in Section 9.3 of the, very long, Technical Reference Manual for the AM3358

Building a DTB

This should simply be done by running make in the dtb directory, with system source code installed in the usual place, /usr/src/sys:

make -C dtb

The resulting DTB file can then be copied to /boot/dtb. It is necessary to instruct the boot loader to use it, as opposed to the default device tree file by placing

fdt_file=bbb-cryptocape.dtb

in /boot/msdos/uenv.txt

Kernel configuration

The BBBC kernel config can be placed in /usr/src/sys/arm/conf as usual and used to build a kernel. The main difference from the generic BEAGLEBONE kernel is the inclusion of the icee EEPROM driver and the DS3231 real time clock driver.