cpu/esp32: use esptool.py from PATH

[gschorcht]

Contribution description

This PR removes the use of esptool.py from ESP32 SDK. Instead, esptool.py installed from pip is used. This makes it possible to flash and reset ESP32 without the SDK installed using PORT.
The documentation is updated to clarify esptool.py installation.

Testing procedure

Generate the documentation with

make doc

and install esptool.py according to the documentation.

Compile and flash any application for an ESP32 board using docker:

BUILD_IN_DOCKER=1 make BOARD=esp32-wroom-32 -C examples/default flash term

If the default port doesn't work, use the PORT variable to define the port, for example:

PORT=/dev/ttyUSB1 BUILD_IN_DOCKER=1 \
make BOARD=esp32-wroom-32 -C examples/default flash term

Issues/PRs references

Related to PR #11646.

[cladmi]

For me the updated documentation makes sense and looks good. (I looked at the html).

It may be better to change already to esptool.py within this PR to match the documentation. I do not mind rebasing.

diff --git a/cpu/esp32/Makefile.include b/cpu/esp32/Makefile.include
index 850a72402..d011791fc 100644
--- a/cpu/esp32/Makefile.include
+++ b/cpu/esp32/Makefile.include
@@ -61,7 +61,7 @@ PSEUDOMODULES += esp_wifi_any
 
 export CPU ?= esp32
 export TARGET_ARCH ?= xtensa-esp32-elf
-export ESPTOOL ?= $(ESP32_SDK_DIR)/components/esptool_py/esptool/esptool.py
+export ESPTOOL ?= esptool.py
 
 USEMODULE += esp_idf
 USEMODULE += esp_idf_driver

[cladmi]

@MrKevinWeiss you were testing the last esp PRs so may be interested

[MrKevinWeiss]

I can go through the procedure after the summit! Ping again if I forget.

[cladmi]

@MrKevinWeiss ping summit is over :)

[MrKevinWeiss]

Many thanks, I am on it!

[MrKevinWeiss]

I was trying to go through the apt-get install esptool however it doesn't seem like there is a version 2.2 available and the one shipped with stock ubuntu 16.04 doesn't have a esptool.py only a esptool. Can someone can confirm that it is not a problem with the documentation only my system not being able to install the correct version?

The pip install stuff works great though.

[cladmi]

Indeed, ubuntu seems to ship it named as esptool (debian does the same)

https://packages.ubuntu.com/xenial/amd64/esptool/filelist
https://packages.ubuntu.com/bionic/all/esptool/filelist
https://packages.ubuntu.com/cosmic/all/esptool/filelist

I think because the first versions were binary versions not implemented in python and they kept the name compatibility.

Also only disco ships a version >=2.2.

https://packages.ubuntu.com/disco/esptool

I do not expect any packages from 'xenial' (16.04) to be supported though.

[cladmi]

The esptool.py is shipped in /usr/share/esptool/esptool.py (as I looked in the file list).

[gschorcht]

Sorry, I'm on vacation and can't do much from here.

The esptool shipped with Ubuntu 16.04 and older Debian versions ist too old. Therefore, the minimum required version in the documentation is version 2.2. That's why you have to use pip for Ubuntu 16.04.

[MrKevinWeiss]

Does this become obsolete with #11108?

[gschorcht]

Hm, if dist/tool/esptool works, it could also be used by ESP32 toolchain.

[gschorcht]

Closed in favor of PR #12750