Bug#868895: xtensa toolchain(s)

[Helmut Grohne <helmut@subdivi.de>]

Hi Jonathan,

On Fri, Aug 03, 2018 at 04:46:16AM +0100, Jonathan McDowell wrote:
> I've been looking at generating binutils + gcc packages based on the
> binutils-source + gcc-7-source packages for the xtensa-lx106 target
> (ESP8266). I have something that seems to be working, and I'm
> considering uploading them, but I don't think it's possible to build a
> single toolchain that will target the ESP8266, ESP32 + ath9k Xtensa
> variants. The xtensa-lx106 binary packages are turning out at about 20M
> between them; is there enough use that it would be worth having all 3
> options present in Debian?

Let me argue that yes, that would be a good idea.

We have esptool in the archive. The esptool comes with a flasher_stub
(https://sources.debian.org/src/esptool/2.5.0+dfsg-1/flasher_stub/).
Presently it cannot be built, because the toolchain would be required
for doing so. It needs the xtensa-lx106-elf and xtensa-esp32-elf
toolchains.

The open-ath9k-htc-firmware package presently builds an xtensa toolchain
from gcc-7 sources during build
https://sources.debian.org/src/open-ath9k-htc-firmware/1.4.0-97-g75b3e59+dfsg-1/debian/cross-toolchain.mk/
using --target xtensa-elf. Having separate binary packages could
simplify the packaging of open-ath9k-htc-firmware.

Maybe the ath9k toolchain is less relevant as most users will be using
open-ath9k-htc-firmware or firmware-atheros. Those that need can quite
easily produce the toolchain from the open-ath9k-htc-firmware source
package. But given the rising popcon of esptool (~200 now), toolchains
for ESP8266 and ESP32 seem sensible to me.

Note that any practical use will also need esp-idf. In particular, the
flasher_stub from esptool needs esp-idf. Do you have any plans for
packaging esp-idf?

Also moving to gcc-8-source seems in order.

Helmut