Cross Compiling macchina.io for Raspberry Pi Zero W

[vardanin]

Raspberry Pi Zero W has a modest 512 MB of RAM, I guess cross compiling is a better solution than direct compiling on the platform, because of that I want to cross compile macchina.io on my Ubuntu 16.04 host and run it on Raspberry Pi Zero W. I follow steps for cross compiling in this article:

https://github.com/macchina-io/macchina.io/wiki/Cross-Compiling-for-Raspberry-Pi-(Raspbian)-and-BeagleBone-Black-(Debian-Stretch)

#1 Can not install libssl-dev:armhf
Command:
$ sudo apt-get install libssl-dev:armhf

Can not locate the package:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package libssl-dev:armhf

#2 Editing configuration file
Which build configuration file is the best choise: ARM-Linux, X-Debian-Stretch-RPi or some other? What we need to redefine in this configuration file for armv6l Raspberry Pi Zero W architecture?

[obiltschnig]

You should do the cross compiling on host using the same Debian release that you are also running on the Raspberry Pi. Everything else is a recipe for disaster. For the current Raspbian Buster, that would be Debian Buster. The X-Debian-Stretch-RPi build config should work for Buster as well.

[vardanin]

I installed Debian Buster 10.3 (x86-64) on my VMware virtual macchine.

Also I downloaded Raspberry Pi Zero GCC cross-compiler:
https://sourceforge.net/projects/raspberry-pi-cross-compilers/files/Raspberry%20Pi%20GCC%20Cross-Compiler%20Toolchains/Buster/GCC%209.2.0/Raspberry%20Pi%201%2C%20Zero/

Following commands are executed:

$ cd ~

$ sudo apt-get install g++ make libssl-dev python

$ git clone https://github.com/macchina-io/macchina.io.git

$ cd macchina.io

$ git checkout master

$ make -s -j2 hosttools

Exporting path to bin folder of cross-compiler
$ export PATH=~/cross-pi-gcc-9.2.0-0/bin/:$PATH

$ POCO_CONFIG=X-Debian-Stretch-RPi LINKMODE=SHARED make -s -j2 DEFAULT_TARGET=shared_release

During compiling, get this error messages for openssl:

** Compiling src/Cipher.cpp (release, shared)
In file included from include/Poco/Crypto/Cipher.h:21,
from src/Cipher.cpp:15:
include/Poco/Crypto/Crypto.h:28:10: fatal error: openssl/opensslv.h: No such file or directory
28 | #include <openssl/opensslv.h>
| ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [/home/marko/macchina.io/platform/build/rules/compile:61: /home/marko/macchina.io/platform/Crypto/obj/Linux/armv7l/release_shared/Cipher.o] Error 1
make[1]: *** [Makefile:160: Crypto-libexec] Error 2
make[1]: *** Waiting for unfinished jobs....
.
.
.
(END of compiling)
(v8::Isolate*, v8::GCType, v8::GCCallbackFlags)’} [-Wcast-function-type]
10326 | reinterpret_castIsolate::GCCallback(callback));
| ^
SOLINK(target) /home/marko/macchina.io/platform/JS/V8/out/Release/obj.target/v8/src/libv8.so
COPY /home/marko/macchina.io/platform/JS/V8/out/Release/lib.target/libv8.so
make: *** [Makefile:76: clean] Error 2

I used original X-Debian-Stretch-RPi configuration file with no change, but time optimization flags on cross-compiler site and X-Debian-Stretch-RPi configuration file are different.

Cross-compiler site:
-march=armv6 -mfloat-abi=hard -mfpu=vfp

X-Debian-Stretch-RPi configuration file:
-march=armv7-a -mfloat-abi=hard -mfpu=neon-vfpv4

Also Raspberry Pi Zero have armv6l instead of armv7l architecture. I tried to compile helloWorld on host and a.out file work on Zero.

[obiltschnig]

You need to have the OpenSSL libraries available for your target (cross-compiled with the same toolchain) as well.

[vardanin]

I tried to compile macchina direct on Raspberry Pi Zero W. For example, Tinkerforge RED Brick and Zero W have similar hardware capabilities, 1GHz CPU and 512 MB RAM. But Tinkerforge RED Brick and all models of Raspberry Pi have ARM v7 architecture, except Raspberry Pi Zero/Zero W which have ARM v6 architecture.

Compiling on my Raspberry Pi Zero W with latest Rasbian Buser terminated during V8 build with unsupported architecture error:

...

** Building shared library (release) /home/pi/macchina.io/platform/lib/Linux/armv6l/libPocoWebTunnel.so.1
gyp: name 'arm_version' is not defined while evaluating condition 'arm_version==7 or arm_version=="default"' in v8/src/v8.gyp
make[2]: *** [Makefile:96: out/Makefile] Error 1
make[1]: *** [Makefile:281: JS/V8-libexec] Error 2
make: *** [Makefile:76: clean] Error 2

Is it possible to run the macchina on Raspberry Pi Zero/Zero W?

[obiltschnig]

It may be that the old ARMv6 architecture is no longer supported by the V8 version we're using. Haven't actually checked. You could try adding the following check to platform/JS/V8/Makefile:

ifeq ($(findstring armv6,$(OSARCH)),armv6)
GYPFLAGS += -Darm_version=6
endif

(right after or before the corresponding check for armv7)