I'm absolutely not a chibios or esp32 expert, but I have had a bit of a poke at it and done an initial ESP32 commit, copied from MSP430X as that's a known small example, and code and compiler settings modified until the toolchain can build something.
This is absolutely not gonna work on an esp32, but it's enough to prove that we have a working xtensa-esp32-elf-* toolchain that can build at least the testhal/ESP32/ESP32DOITDEVKITV1/ADC/ example, and a basic layout of folders we might be able to follow.
In short, I basically commented out all the msp430 assembler bits that aren't valid esp32 assembler, dug around on the internet for enough plausible linker bits ( from espressif's IDF for freertos or whatever ), and messed with the Makefile and headers and code in testhal/ESP32/ESP32DOITDEVKITV1/ADC/ and elsewhere till the thing compiled. I consider that a success, a very , very hacky one.

https://github.com/davidbuzz/ChibiOS-Co ... /esp32-wip