[OpenWrt-Users] Confusion on whether the toolchain is for 32-bit ARM or 64-bit ARM

[Damiano Verzulli]

[...]
Now, we wish to use the toolchain for our project, but I am confused
as to whether the toolchain supports (only) 32-bit ARM, or (only)
64-bit ARM, or both 32-bit and 64-bit ARM. So, will be thankful if the
experts can help me on that.

Hi Ajay,

as it looks like your real problem is "building your project" (and, as
such, the "toolchain" is a side-problem, not the main one), I'd suggest a
slightly different approach.

Recently I spent LOTs of efforts in building an OpenWRT package "from
scratch" (I mean: a package NOT included in the OpenWRT repositories; a
package to be built from the source code, in the .tar.gz format).

Exactly like you, my first problem related to cross-compilation
capabilities; in my case, I built for a TP-LINK WDR-4300, with this CPU:

--------------------------------------------
***@WRT:~# cat /proc/cpuinfo
system type : Atheros AR9344 rev 2
machine : TP-LINK TL-WDR3600/4300/4310
...
cpu model : MIPS 74Kc V4.12
...
isa : mips1 mips2 mips32r1 mips32r2
ASEs implemented : mips16 dsp dsp2
--------------------------------------------

As for "architecture" (32 vs 64 bit), even if in my case things were very
clear (as the WDR4300 CPU is clearly 32 bit) I REALLY DID _NOT_ NEED to
take care of them!

Specifically, I decided to deal with the "Official OpenWRT SDK":

https://openwrt.org/docs/guide-developer/using_the_sdk

that: "... is a pre-compiled toolchain designed to cross compile packages
for a specific target without compiling the whole system from scratch...."

As you'll quickly discover, such an SDK is _ALREADY_ built for _EVERY_
platform supported by OpenWRT.
I mean: if you're planning to build _YOUR_ package for a specific platform
(eg: ar71xx) then you simply have to download related SDK FOR_THAT_PLATFORM
and you'll get all ready to go!

Unfortunately you're mentioning only "Allwinner A1x" and I really don't
know "which" OpenWRT platform apply to it:
https://downloads.openwrt.org/releases/17.01.4/targets/
Should it be "arm64", you can find the SDK at:
https://downloads.openwrt.org/releases/17.01.4/targets/arm64/generic/lede-sdk-17.01.4-arm64_gcc-5.4.0_musl-1.1.16.Linux-x86_64.tar.xz

As I said, I spent _LOTS_ of time investigating such activities and....
should you need further details, feel free to give a look to the (hopefully
detailed) guide that I scratched down a couple of days ago [1].

Hope it helps!

Cheers,
DV

[1]
http://dvblog.soabit.com/building-custom-openwrt-packages-an-hopefully-complete-guide/
--
Damiano Verzulli
e-mail: ***@verzulli.it
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